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Find video protocols related to scientific articles indexed in Pubmed.
Single-cell copy number analysis of prostate cancer cells captured with geometrically enhanced differential immunocapture microdevices.
Anal. Chem.
PUBLISHED: 11-04-2014
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Limited access to tumor tissue makes repeated sampling and real-time tracking of cancer progression infeasible. Circulating tumor cells (CTCs) provide the capacity for real-time genetic characterization of a disseminating tumor cell population via a simple blood draw. However, there is no straightforward method to analyze broadscale genetic rearrangements in this heterogeneous cell population at the single cell level. We present a one-step controllable chemical extraction of whole nuclei from prostate cancer cells captured using geometrically enhanced differential immunocapture (GEDI) microdevices. We have successfully used copy number profile analysis to differentiate between two unique cancer cell line populations of metastatic origin (LNCaP and VCaP) and to analyze key mutations important in disease progression.
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Sofosbuvir and Ribavirin for Treatment of Compensated Recurrent Hepatitis C Virus Infection After Liver Transplantation.
Gastroenterology
PUBLISHED: 07-29-2014
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Interferon alfa-based regimens used to treat recurrent hepatitis C virus (HCV) infection after liver transplantation are poorly tolerated, associated with generally modest efficacy, and can interact with immunosuppressive agents. We evaluated the efficacy and safety of an interferon-free regimen of the nucleotide polymerase inhibitor sofosbuvir combined with ribavirin for 24 weeks in treating post-transplant HCV infection.
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Characterization of microfluidic shear-dependent epithelial cell adhesion molecule immunocapture and enrichment of pancreatic cancer cells from blood cells with dielectrophoresis.
Biomicrofluidics
PUBLISHED: 07-01-2014
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Current microfluidic techniques for isolating circulating tumor cells (CTCs) from cancer patient blood are limited by low capture purity, and dielectrophoresis (DEP) has the potential to complement existing immunocapture techniques to improve capture performance. We present a hybrid DEP and immunocapture Hele-Shaw flow cell to characterize DEP's effects on immunocapture of pancreatic cancer cells (Capan-1, PANC-1, and BxPC-3) and peripheral blood mononuclear cells (PBMCs) with an anti-EpCAM (epithelial cell adhesion molecule) antibody. By carefully specifying the applied electric field frequency, we demonstrate that pancreatic cancer cells are attracted to immunocapture surfaces by positive DEP whereas PBMCs are repelled by negative DEP. Using an exponential capture model to interpret our capture data, we show that immunocapture performance is dependent on the applied DEP force sign and magnitude, cell surface EpCAM expression level, and shear stress experienced by cells flowing in the capture device. Our work suggests that DEP can not only repel contaminating blood cells but also enhance capture of cancer cell populations that are less likely to be captured by traditional immunocapture methods. This combination of DEP and immunocapture techniques to potentially increase CTC capture purity can facilitate subsequent biological analyses of captured CTCs and research on cancer metastasis and drug therapies.
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The use of transient elastography and FibroTest for monitoring hepatotoxicity in patients receiving methotrexate for psoriasis.
JAMA Dermatol
PUBLISHED: 06-27-2014
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There is a need for noninvasive tools to monitor hepatotoxicity in patients with psoriasis who are receiving methotrexate sodium.
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Hidradenitis suppurativa: the role of immune dysregulation.
Int. J. Dermatol.
PUBLISHED: 06-25-2014
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Hidradenitis suppurativa (HS) is a chronic relapsing inflammatory disease of follicular occlusion characterized by boils, sinus tracts, fistulae, and scarring. It has a significant underestimated morbidity. Antimicrobial, immunosuppressive, anti-androgenic, and surgical approaches have been used with varying results. Knowledge of the pathogenesis of HS is fragmented, and treatment choices have hitherto been empiric without an exact understanding of the scientific basis for their use. Tumor necrosis factor-? inhibitors have shown promise in the treatment of HS in recent years, and the concept of HS as an immunological condition has come to the fore. The focus of this review is to discuss the immunological abnormalities underpinning HS as elucidated to date.
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GRAPPA Fellows Symposium Adjacent to the European Academy of Dermatology and Venereology (EADV) Congress, Istanbul, 2013: a meeting report.
J. Rheumatol.
PUBLISHED: 06-03-2014
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The Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) organized its second Fellows Symposium adjacent to the European Academy of Dermatology and Venereology (EADV) congress in Istanbul in October 2013. Wolf-Henning Boehncke from Geneva, Brian Kirby from Dublin, and Diamant Thaci from Lübeck formed the faculty. The 9 best-ranked abstracts submitted to this symposium were presented and discussed in detail. Five abstracts focused on comorbidities in patients with psoriasis or psoriatic arthritis; summaries of all abstracts are included herein.
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Circulating tumor cells in prostate cancer diagnosis and monitoring: an appraisal of clinical potential.
Mol Diagn Ther
PUBLISHED: 05-10-2014
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Circulating tumor cells (CTCs) have emerged as a viable solution to the lack of tumor tissue availability for patients with a variety of solid tumors, including prostate cancer. Different approaches have been used to capture this tumor cell population and several of these techniques have been used to assess the potential role of CTCs as a biological marker to predict treatment efficacy and clinical outcome. CTCs are now considered a strong tool to understand the molecular characteristics of prostate cancer, and to be used and analyzed as a 'liquid biopsy' in the attempt to grasp the biological portrait of the disease in the individual patient.
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Psoriasis beyond the skin: a review of the literature on cardiometabolic and psychological co-morbidities of psoriasis.
Eur J Dermatol
PUBLISHED: 04-23-2014
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Psoriasis is increasingly associated with a range of co-morbid diseases and risk factors. Patients with co-morbidities are more likely to need hospitalisation for non-dermatological conditions, and incur greater total costs than those without co-morbidities. A literature review was conducted on two of the most common co-morbidities of psoriasis (cardiovascular (CV) and psychological co-morbidities), to establish their incidence and impact and to raise awareness of unanswered questions and highlight knowledge gaps. A large number of small controlled or cross-sectional studies report increased prevalence of cardiometabolic and psychological co-morbidities in psoriasis patients. A number of large cohort studies documented the incidence of various cardiometabolic co-morbidities. Severe psoriasis is associated with increased mortality, and the most common cause of death is CV disease. Studies on the management of co-morbidities and their impact on psoriasis treatment are scarce. Many questions on the co-morbidities of psoriasis remain to be answered.
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Investigating the contribution of CYP2J2 to ritonavir metabolism in vitro and in vivo.
Biochem. Pharmacol.
PUBLISHED: 04-22-2014
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Ritonavir, an HIV protease inhibitor, is successfully used for the prevention and treatment of HIV infections. Ritonavir pharmacokinetics are complicated by inhibition, induction and pharmacogenetics of cytochrome P450 (CYP) enzymes mediating its clearance. This investigation revealed that CYP2J2, along with CYP3A4/5 and CYP2D6, efficiently metabolizes ritonavir, and to a CYP2J2-specific (minor) metabolite. Chemical inhibition of ritonavir metabolism, clearance, KI/kinact and abundance of CYP2J2 in liver microsomes were evaluated and then applied to an in vitro-in vivo static scaling model to estimate the contribution of each isozyme, as a function of CYP abundance, activity, and genotype. Disposition of the CYP2J2-specific metabolite was also evaluated in vivo. In plasma, metabolite abundance was well above previously reported levels with circulating concentrations measured at 2 ?M for the main hydroxylisopropyl metabolite. Ritonavir and metabolite plasma profiles were simulated using Simcyp(®). A modest (2-6%) contribution of CYP2J2 to ritonavir clearance is predicted which increases to more than 20% in subjects carrying CYP2D6 poor metabolizer polymorphisms and CYP3A4 irreversible inhibition. These results indicate that minor drug metabolizing enzymes could become quantitatively important in RTV clearance if main metabolic pathways are impeded.
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AP1S3 mutations are associated with pustular psoriasis and impaired Toll-like receptor 3 trafficking.
Am. J. Hum. Genet.
PUBLISHED: 04-09-2014
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Adaptor protein complex 1 (AP-1) is an evolutionary conserved heterotetramer that promotes vesicular trafficking between the trans-Golgi network and the endosomes. The knockout of most murine AP-1 complex subunits is embryonically lethal, so the identification of human disease-associated alleles has the unique potential to deliver insights into gene function. Here, we report two founder mutations (c.11T>G [p.Phe4Cys] and c.97C>T [p.Arg33Trp]) in AP1S3, the gene encoding AP-1 complex subunit ?1C, in 15 unrelated individuals with a severe autoinflammatory skin disorder known as pustular psoriasis. Because the variants are predicted to destabilize the 3D structure of the AP-1 complex, we generated AP1S3-knockdown cell lines to investigate the consequences of AP-1 deficiency in skin keratinocytes. We found that AP1S3 silencing disrupted the endosomal translocation of the innate pattern-recognition receptor TLR-3 (Toll-like receptor 3) and resulted in a marked inhibition of downstream signaling. These findings identify pustular psoriasis as an autoinflammatory phenotype caused by defects in vesicular trafficking and demonstrate a requirement of AP-1 for Toll-like receptor homeostasis.
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Microfluidic immunocapture of circulating pancreatic cells using parallel EpCAM and MUC1 capture: characterization, optimization and downstream analysis.
Lab Chip
PUBLISHED: 03-28-2014
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We have developed and optimized a microfluidic device platform for the capture and analysis of circulating pancreatic cells (CPCs) and pancreatic circulating tumor cells (CTCs). Our platform uses parallel anti-EpCAM and cancer-specific mucin 1 (MUC1) immunocapture in a silicon microdevice. Using a combination of anti-EpCAM and anti-MUC1 capture in a single device, we are able to achieve efficient capture while extending immunocapture beyond single marker recognition. We also have detected a known oncogenic KRAS mutation in cells spiked in whole blood using immunocapture, RNA extraction, RT-PCR and Sanger sequencing. To allow for downstream single-cell genetic analysis, intact nuclei were released from captured cells by using targeted membrane lysis. We have developed a staining protocol for clinical samples, including standard CTC markers; DAPI, cytokeratin (CK) and CD45, and a novel marker of carcinogenesis in CPCs, mucin 4 (MUC4). We have also demonstrated a semi-automated approach to image analysis and CPC identification, suitable for clinical hypothesis generation. Initial results from immunocapture of a clinical pancreatic cancer patient sample show that parallel capture may capture more of the heterogeneity of the CPC population. With this platform, we aim to develop a diagnostic biomarker for early pancreatic carcinogenesis and patient risk stratification.
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Electrokinetic measurements of thin Nafion films.
Langmuir
PUBLISHED: 02-14-2014
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We perform an electrokinetic characterization of ~300 nm Nafion films deposited on glass slides over a relatively unexplored region of ionic strength and pH. Owing to the small pore size of the Nafion, we probe the Nafion-fluid interface with the streaming potential measurement, and we probe ionic transport through the entire thickness of the Nafion film with the conductivity measurements. By applying a transport model for each of these measurements, we show that the inferred fixed charge density and characteristic fluid resistance length is different in each case. Analyzing our results with data from the literature, we suggest that our result is consistent with a thin Nafion film that is both nonuniform and weakly hydrated. Our regimen of experimentation and analysis may be generalized to characterize other porous and charged layers.
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Treating moderate to severe psoriasis - best use of biologics.
Expert Rev Clin Immunol
PUBLISHED: 12-27-2013
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This review focuses on the efficacy, safety and best use of biologic agents in moderate-to-severe psoriasis. Recommendations from two recent guidelines are summarised. The NICE Guidelines 2012 provide recommendations on best practice for prescribing biologics. The German S3 Guidelines are based on a systematic review of published studies and report the efficacy of biologics and guidelines for treatment. Data on the safety of biologics are available for up to 5 years in psoriasis and are on the whole reassuring. Registry data is evolving and will provide data on safety to help inform long-term monitoring of patients with psoriasis on biologics agents. New anti-interleukin-17 (IL17) and anti-IL17RA biologics are in Phase 3 clinical trials and may prove to be more effective than existing biologics.
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Detection of Circulating Pancreas Epithelial Cells in Patients with Pancreatic Cystic Lesions.
Gastroenterology
PUBLISHED: 11-25-2013
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Hematogenous dissemination is thought to be a late event in cancer progression. We showed recently that pancreas cells can be detected in the bloodstream before tumor formation, in a genetic model of pancreatic ductal adenocarcinoma (PDAC). To confirm these findings in humans, we used microfluidic geometrically enhanced immunocapture to detect circulating pancreas epithelial cells (CECs) in patient blood samples. We captured >3 CECs/ml in 7 of 21 (33%) of patients with cystic lesions and no clinical diagnosis of cancer (Sendai criteria negative), 8 of 11 (73%) with PDAC, and in 0 of 19 patients without cysts or cancer (controls). These findings indicate that cancer cells are present in the circulation of patients before tumors develop, which might be used in risk assessment.
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Isolation of breast cancer and gastric cancer circulating tumor cells by use of an anti HER2-based microfluidic device.
Lab Chip
PUBLISHED: 11-07-2013
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Circulating tumor cells (CTCs) have emerged as a reliable source of tumor cells, and their concentration has prognostic implications. CTC capture offers real-time access to cancer tissue without the need of an invasive biopsy, while their phenotypic and molecular interrogation can provide insight into the biological changes of the tumor that occur during treatment. The majority of the CTC capture methods are based on EpCAM expression as a surface marker of tumor-derived cells. However, EpCAM protein expression levels can be significantly down regulated during cancer progression as a consequence of the process of epithelial to mesenchymal transition. In this paper, we describe a novel HER2 (Human Epidermal Receptor 2)-based microfluidic device for the isolation of CTCs from peripheral blood of patients with HER2-expressing solid tumors. We selected HER2 as an alternative to EpCAM as the receptor is biologically and therapeutically relevant in several solid tumors, like breast cancer (BC), where it is overexpressed in 30% of the patients and expressed in 90%, and gastric cancer (GC), in which HER2 presence is identified in more than 60% of the cases. We tested the performance of various anti HER2 antibodies in a panel of nine different BC cell lines with varying HER2 protein expression levels, using immunoblotting, confocal microscopy, live cells imaging and flow cytometry analyses. The antibody associated with the highest capture efficiency and sensitivity for HER2 expressing cells on the microfluidic device was the one that performed best in live cells imaging and flow cytometry assays as opposed to the fixed cell analyses, suggesting that recognition of the native conformation of the HER2 extracellular epitope on living cells was essential for specificity and sensitivity of CTC capture. Next, we tested the performance of the HER2 microfluidic device using blood from metastatic breast and gastric cancer patients. The HER2 microfluidic device exhibited CTC capture in 9/9 blood samples. Thus, the described HER2-based microfluidic device can be considered as a valid clinically relevant method for CTC capture in HER2 expressing solid cancers.
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GRAPPA Fellows Symposium adjacent to the European Academy of Dermatology and Venerology meeting, Verona, 2012: a meeting report.
J. Rheumatol.
PUBLISHED: 08-03-2013
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The Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) organized a Fellows Symposium adjacent to the European Academy of Dermatology and Venerology (EADV) spring meeting in Verona, Italy, in 2012. Wolf-Henning Boehncke from Geneva and Brian Kirby from Dublin formed the faculty. Five papers were presented, followed by extended discussions among participants and faculty. Two contributions were on comorbidities of psoriasis patients and 2 on treatment of non-plaque-type psoriasis; the fifth presentation was a discussion of possible modes of action of vitamin D derivatives in the treatment of psoriasis. Summaries of all 5 papers are included here.
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The dermatological consequences of obesity.
Int. J. Dermatol.
PUBLISHED: 07-23-2013
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Obesity is emerging as a global epidemic with at least 300 million people thought to be obese worldwide. This has implications for health professionals including dermatologists. Recent interest has focused on the role of obesity in psoriasis, but obesity is implicated in many dermatoses. Perhaps most worrying is emerging data which suggest that obesity may constitute a risk factor for the development of skin cancer. Its rising incidence ensures that obesity-related skin disease will represent an increasing proportion of dermatologists work load. In this article, we review dermatoses associated with obesity and review the epidemiology and treatment for obesity.
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Culture of primary rat hippocampal neurons: design, analysis, and optimization of a microfluidic device for cell seeding, coherent growth, and solute delivery.
Biomed Microdevices
PUBLISHED: 07-16-2013
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We present the design, analysis, construction, and culture results of a microfluidic device for the segregation and chemical stimulation of primary rat hippocampal neurons. Our device is designed to achieve spatio-temporal solute delivery to discrete sections of neurons with mitigated mechanical stress. We implement a geometric guidance technique to direct axonal processes of the neurons into specific areas of the device to achieve solute segregation along routed cells. Using physicochemical modeling, we predict flows, concentration profiles, and mechanical stresses within pertiment sections of the device. We demonstrate cell viability and growth within the closed device over a period of 11 days. Additionally, our modeling methodology may be generalized and applied to other device geometries.
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Enrichment of prostate cancer cells from blood cells with a hybrid dielectrophoresis and immunocapture microfluidic system.
Biomed Microdevices
PUBLISHED: 06-29-2013
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The isolation of circulating tumor cells (CTCs) from cancer patient blood is a technical challenge that is often addressed by microfluidic approaches. Two of the most prominent techniques for rare cancer cell separation, immunocapture and dielectrophoresis (DEP), are currently limited by a performance tradeoff between high efficiency and high purity. The development of a platform capable of these two performance criteria can potentially be facilitated by incorporating both DEP and immunocapture. We present a hybrid DEP-immunocapture system to characterize how DEP controls the shear-dependent capture of a prostate cancer cell line, LNCaP, and the nonspecific adhesion of peripheral blood mononuclear cells (PBMCs). Characterization of cell adhesion with and without DEP effects was performed in a Hele-Shaw flow cell that was functionalized with the prostate-specific monoclonal antibody, J591. In this model system designed to make nonspecific PBMC adhesion readily apparent, we demonstrate LNCaP enrichment from PBMCs by precisely tuning the applied AC electric field frequency to enhance immunocapture of LNCaPs and reduce nonspecific adhesion of PBMCs with positive and negative DEP, respectively. Our work shows that DEP and immunocapture techniques can work synergistically to improve cancer cell capture performance, and it informs the design of future hybrid DEP-immunocapture systems with improved CTC capture performance to facilitate research on cancer metastasis and drug therapies.
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Characterization of a hybrid dielectrophoresis and immunocapture microfluidic system for cancer cell capture.
Electrophoresis
PUBLISHED: 05-23-2013
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The capture of circulating tumor cells (CTCs) from cancer patient blood enables early clinical assessment as well as genetic and pharmacological evaluation of cancer and metastasis. Although there have been many microfluidic immunocapture and electrokinetic techniques developed for isolating rare cancer cells, these techniques are often limited by a capture performance tradeoff between high efficiency and high purity. We present the characterization of shear-dependent cancer cell capture in a novel hybrid DEP-immunocapture system consisting of interdigitated electrodes fabricated in a Hele-Shaw flow cell that was functionalized with a monoclonal antibody, J591, which is highly specific to prostate-specific membrane antigen expressing prostate cancer cells. We measured the positive and negative DEP response of a prostate cancer cell line, LNCaP, as a function of applied electric field frequency, and showed that DEP can control capture performance by promoting or preventing cell interactions with immunocapture surfaces, depending on the sign and magnitude of the applied DEP force, as well as on the local shear stress experienced by cells flowing in the device. This work demonstrates that DEP and immunocapture techniques can work synergistically to improve cell capture performance, and it will aid in the design of future hybrid DEP-immunocapture systems for high-efficiency CTC capture with enhanced purity.
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Force and flux relations for flows of ionic solutions between parallel plates with porous and charged layers.
Phys Rev E Stat Nonlin Soft Matter Phys
PUBLISHED: 05-22-2013
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We derive coefficients of the electrokinetic coupling matrix (?_{11}, ?_{12}, and ?_{21}) for the flow of an ionic solution through a parallel-plate geometry having porous and charged layers grafted onto a solid surface with a known potential and demonstrate Onsager reciprocity for the cross terms (i.e., ?_{12}=?_{21}). Our results enable the prediction of system outputs in the solid-porous-fluid system from parameters that are either known or may be measured and inferred. These electrokinetic coupling coefficients are in terms of the potential, ?, and fixed charge, ?_{f}, only, removing dependence on field gradients and fluid velocity. Additionally, we present simplified expressions of these coupling coefficients in limiting regions of the parameter space. Away from these limits, we present numerical results demonstrating the facility of our functional form for facile numerical approximation and report the utility and accuracy of our analytical approximations.
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Transport and collision dynamics in periodic asymmetric obstacle arrays: rational design of microfluidic rare-cell immunocapture devices.
Phys Rev E Stat Nonlin Soft Matter Phys
PUBLISHED: 05-21-2013
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Microfluidic obstacle arrays have been used in numerous applications, and their ability to sort particles or capture rare cells from complex samples has broad and impactful applications in biology and medicine. We have investigated the transport and collision dynamics of particles in periodic obstacle arrays to guide the design of convective, rather than diffusive, transport-based immunocapture microdevices. Ballistic and full computational fluid dynamics simulations are used to understand the collision modes that evolve in cylindrical obstacle arrays with various geometries. We identify previously unrecognized collision mode structures and differential size-based collision frequencies that emerge from these arrays. Previous descriptions of transverse displacements that assume unidirectional flow in these obstacle arrays cannot capture mode transitions properly as these descriptions fail to capture the dependence of the mode transitions on column spacing and the attendant change in the flow field. Using these analytical and computational simulations, we elucidate design parameters that induce high collision rates for all particles larger than a threshold size or selectively increase collision frequencies for a narrow range of particle sizes within a polydisperse population. Furthermore, we investigate how the particle Péclet number affects collision dynamics and mode transitions and demonstrate that experimental observations from various obstacle array geometries are well described by our computational model.
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Detection of algal lipid accumulation due to nitrogen limitation via dielectric spectroscopy of Chlamydomonas reinhardtii suspensions in a coaxial transmission line sample cell.
Bioresour. Technol.
PUBLISHED: 04-06-2013
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In this study, dielectric characterization of algae cell suspensions was used to detect lipid accumulation due to nitrogen starvation. Wild-type Chlamydomonas reinhardtii (CC-125) was cultivated in replete and nitrogen-limited conditions in order to achieve a range of lipid contents, as confirmed by Nile Red fluorescence measurements. A vector network analyzer was used to measure the dielectric scattering parameters of a coaxial region of concentrated cell suspension. The critical frequency fc of the normalized transmission coefficient |S21(*)| decreased with increasing lipid content but did not change with cell concentration. These observations were consistent with a decrease in cytoplasmic conductivity due to lipid accumulation in the preliminary transmission line model. This dielectric sensitivity to lipid content will facilitate the development of a rapid, noninvasive method for algal lipid measurement that could be implemented in industrial settings without the need for specialized staff and analytical facilities.
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Comparative evaluation of the degree of pegylation of poly(lactic-co-glycolic acid) nanoparticles in enhancing central nervous system delivery of loperamide.
J. Pharm. Pharmacol.
PUBLISHED: 04-04-2013
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In this study, we examined the relative cellular uptake of nanoparticles (NPs) formulated using poly(lactic-co-glycolic acid) (PLGA) polymers with increasing degree of pegylation (PLGA-PEG) and their potential to deliver loperamide to the brain of a mouse.
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Microfluidic enrichment of mouse epidermal stem cells and validation of stem cell proliferation in vitro.
Tissue Eng Part C Methods
PUBLISHED: 03-18-2013
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Bulge stem cells reside in the lowest permanent portion of hair follicles and are responsible for the renewal of these follicles along with the repair of the epidermis during wound healing. These cells are identified by surface expression of CD34 and the ?6-integrin. When CD34 and ?6 double-positive cells are isolated and implanted into murine skin, they give rise to epidermis and hair follicle structures. The current gold standard for isolation of these stem cells is fluorescence-activated cell sorting (FACS) based on cell surface markers. Here, we describe an alternative method for CD34 bulge stem cell isolation: a microfluidic platform that captures stem cells based on cell surface markers. This method is relatively fast, requiring 30 ?min of time from direct introduction of murine skin tissue digestate into a two-stage microfluidic device to one-pass elution of CD34(+) enriched cells with a purity of 55.8% ± 5.1%. The recovered cells remain viable and formed colonies with characteristic morphologies. When grown in culture, enriched cells contain a larger ?6(+) population than un-enriched cells.
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Methylchloroisothiazolinone and methylisothiazolinone allergic contact dermatitis and the effect of patch test concentration.
Dermatitis
PUBLISHED: 03-12-2013
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The isothiazolinones methylchloroisothiazolinone and methylisothiazolinone (MCI/MI) are the active ingredients in a frequently used preservative in cosmetic, household, and industrial products.
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Complex drug interactions of the HIV protease inhibitors 3: effect of simultaneous or staggered dosing of digoxin and ritonavir, nelfinavir, rifampin, or bupropion.
Drug Metab. Dispos.
PUBLISHED: 12-21-2011
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As part of a larger clinical drug-drug interaction (DDI) study aimed at in vitro to in vivo prediction of HIV protease inhibitor metabolic and transporter-based DDIs, we measured the inductive (staggered administration) and inductive plus inhibitory (simultaneously administered) effect of multiple dose ritonavir (RTV), nelfinavir (NFV), or rifampin (RIF) on the pharmacokinetics of the P-glycoprotein probe, digoxin (DIG), when administered simultaneously or staggered with the protease inhibitors or RIF. In both cases, NFV did not significantly affect DIG disposition. RTV decreased DIG renal clearance (Cl(renal)) when administered simultaneously or staggered but significantly increased DIG area under the curve from time zero to 24 h (AUC(0-24 h)) only when administered simultaneously. RIF decreased DIG AUC(0-24 h) only when RIF and DIG administration was staggered. When RIF and DIG were administered simultaneously, DIG maximal observed plasma concentration and area under the curve from time zero to 4 h were significantly increased, and DIG Cl(renal) was decreased. An unexpected and potentially clinically significant DDI was observed between DIG and the CYP2B6 probe, bupropion, which decreased DIG AUC(0-24 h) 1.6-fold and increased Cl(renal) 1.8-fold. Because this was an unexpected DDI and our studies were not specifically designed to quantify this interaction, further studies are required to confirm the interaction and understand the mechanistic basis of the DDI. In summary, RTV or NFV do not induce P-glycoprotein activity measured with DIG, and RIF does so only under staggered administration.
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HLA associations reveal genetic heterogeneity in psoriatic arthritis and in the psoriasis phenotype.
Arthritis Rheum.
PUBLISHED: 10-17-2011
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Rigorously ascertained cases of psoriatic arthritis in subjects presenting to a rheumatology unit were compared with cases of psoriasis in subjects presenting to a dermatology unit, where subjects with musculoskeletal features were excluded, to address 1) the extent to which the contribution of the major histocompatibility complex (MHC) to psoriatic arthritis susceptibility resembles that in psoriasis, and 2) whether MHC genes determine quantitative traits within the psoriatic arthritis phenotype.
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Complex drug interactions of HIV protease inhibitors 2: in vivo induction and in vitro to in vivo correlation of induction of cytochrome P450 1A2, 2B6, and 2C9 by ritonavir or nelfinavir.
Drug Metab. Dispos.
PUBLISHED: 09-19-2011
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Drug-drug interactions (DDIs) with the HIV protease inhibitors (PIs) are complex, paradoxical (e.g., ritonavir/alprazolam), and involve multiple mechanisms. As part of a larger study to better understand these DDIs and to devise a framework for in vitro to in vivo prediction of these DDIs, we determined the inductive effect of ?2 weeks of administration of two prototypic PIs, nelfinavir (NFV), ritonavir (RTV), and rifampin (RIF; induction positive control) on the cytochrome P450 enzymes CYP1A2, CYP2B6, CYP2C9, and CYP2D6 and the inductive or inductive plus inhibitory effect of NFV, RTV, or RIF on CYP3A and P-glycoprotein in healthy human volunteers. Statistically significant induction of CYP1A2 (2.1-, 2.9-, and 2.2-fold), CYP2B6 (1.8-, 2.4-, and 4-fold), and CYP2C9 (1.3-, 1.8-, and 2.6-fold) was observed after NFV, RTV, or RIF treatment, respectively (as expected, CYP2D6 was not induced). Moreover, we accurately predicted the in vivo induction of these enzymes by quantifying their induction by the PIs in human hepatocytes and by using RIF as an in vitro to in vivo scalar. On the basis of the modest in vivo induction of CYP1A2, CYP2B6, or CYP2C9, the in vivo paradoxical DDIs with the PIs are likely explained by mechanisms other than induction of these enzymes such as induction of other metabolic enzymes, transporters, or both.
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Micro-total analysis system for virus detection: microfluidic pre-concentration coupled to liposome-based detection.
Anal Bioanal Chem
PUBLISHED: 06-29-2011
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An integrated microfluidic biosensor is presented that combines sample pre-concentration and liposome-based signal amplification for the detection of enteric viruses present in environmental water samples. This microfluidic approach overcomes the challenges of long assay times of cell culture-based methods and the need to extensively process water samples to eliminate inhibitors for PCR-based methods. Here, viruses are detected using an immunoassay sandwich approach with the reporting antibodies tagged to liposomes. Described is the development of the integrated device for the detection of environmentally relevant viruses using feline calicivirus (FCV) as a model organism for human norovirus. In situ fabricated nanoporous membranes in glass microchannels were used in conjunction with electric fields to achieve pre-concentration of virus-liposome complexes and therefore enhance the antibody-virus binding efficiency. The concentrated complexes were eluted to a detection region downstream where captured liposomes were lysed to release fluorescent dye molecules that were then quantified using image processing. This system was compared to an optimized electrochemical liposome-based microfluidic biosensor without pre-concentration. The limit of detection of FCV of the integrated device was at 1.6 × 10(5) PFU/mL, an order of magnitude lower than that obtained using the microfluidic biosensor without pre-concentration. This significant improvement is a key step toward the goal of using this integrated device as an early screening system for viruses in environmental water samples.
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Rare Cell Capture in Microfluidic Devices.
Chem Eng Sci
PUBLISHED: 05-03-2011
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This article reviews existing methods for the isolation, fractionation, or capture of rare cells in microfluidic devices. Rare cell capture devices face the challenge of maintaining the efficiency standard of traditional bulk separation methods such as flow cytometers and immunomagnetic separators while requiring very high purity of the target cell population, which is typically already at very low starting concentrations. Two major classifications of rare cell capture approaches are covered: (1) non-electrokinetic methods (e.g., immobilization via antibody or aptamer chemistry, size-based sorting, and sheath flow and streamline sorting) are discussed for applications using blood cells, cancer cells, and other mammalian cells, and (2) electrokinetic (primarily dielectrophoretic) methods using both electrode-based and insulative geometries are presented with a view towards pathogen detection, blood fractionation, and cancer cell isolation. The included methods were evaluated based on performance criteria including cell type modeled and used, number of steps/stages, cell viability, and enrichment, efficiency, and/or purity. Major areas for improvement are increasing viability and capture efficiency/purity of directly processed biological samples, as a majority of current studies only process spiked cell lines or pre-diluted/lysed samples. Despite these current challenges, multiple advances have been made in the development of devices for rare cell capture and the subsequent elucidation of new biological phenomena; this article serves to highlight this progress as well as the electrokinetic and non-electrokinetic methods that can potentially be combined to improve performance in future studies.
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Automated dielectrophoretic characterization of Mycobacterium smegmatis.
Anal. Chem.
PUBLISHED: 04-04-2011
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We report the positive dielectrophoretic (pDEP) characterization of wild-type and ethambutol-treated Mycobacterium smegmatis populations via automated pDEP cell trapping experiments. The automated technique was validated by measurements of carboxylate-modified polystyrene microspheres and Escherichia coli . The characterization of M. smegmatis identifies a key frequency regime where the membrane-specific action of ethambutol leads to a change in the cellular dielectrophoretic response. This work represents the first such characterization of Mycobacteria and highlights the potential for DEP measurements to measure changes in mycobacterial membrane properties associated with chemical treatments or genetic mutation.
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The psoriatic march: a concept of how severe psoriasis may drive cardiovascular comorbidity.
Exp. Dermatol.
PUBLISHED: 03-18-2011
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There is increasing awareness that psoriasis is more than skin deep. Several recent reviews focussed on biomarkers indicating the systemic dimension of psoriasis and the aspect of comorbidity psoriasis shares with other chronic inflammatory diseases, such as Crohns disease and rheumatoid arthritis. Of emerging significance is the relationship to cardiovascular disease, as this contributes substantially to the patients increased mortality. In this viewpoint, we examine currently available evidence favouring the concept of a causal link between psoriasis and cardiovascular disease: systemic inflammation may cause insulin resistance, which in turn triggers endothelial cell dysfunction, leading to atherosclerosis and finally myocardial infarction or stroke. While this psoriatic march is not yet formally proven, it raises clinically and academically relevant questions, and gains support by recent observations of numerous investigators.
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Ambient pressure effects on the electrokinetic potential of Zeonor-water interfaces.
J Colloid Interface Sci
PUBLISHED: 03-17-2011
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Using phase-sensitive streaming potential experiments in a vacuum chamber, we demonstrate that lowering the ambient pressure of the air surrounding a hydrophobic, Zeonor microfluidic substrate results in a decrease in the time scale required for equilibration of the electrokinetic potential. At ambient air pressures below 0.74 atm, the electrokinetic potential changes from ?-84 mV to ?-11 mV in 5 h, while the same decrease occurs in a period of over 200 h when the system is at 1 atm. Returning a sub-atmospheric system (where the electrokinetic potential had equilibrated to -11 mV) to atmospheric pressure did not result in any additional change in the electrokinetic potential. This can be described as a type of hysteresis of the electrokinetic potential with dissolved gas concentration. No time or pressure dependence was observed for the electrokinetic potential of hydrophilic (silica) substrates.
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Complex drug interactions of HIV protease inhibitors 1: inactivation, induction, and inhibition of cytochrome P450 3A by ritonavir or nelfinavir.
Drug Metab. Dispos.
PUBLISHED: 03-15-2011
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Conflicting drug-drug interaction (DDI) studies with the HIV protease inhibitors (PIs) suggest net induction or inhibition of intestinal or hepatic CYP3A. As part of a larger DDI study in healthy volunteers, we determined the effect of extended administration of two PIs, ritonavir (RTV) or nelfinavir (NFV), or the induction-positive control rifampin on intestinal and hepatic CYP3A activity as measured by midazolam (MDZ) disposition after a 14-day treatment with the PI in either staggered (MDZ ?12 h after PI) or simultaneous (MDZ and PI coadministered) manner. Oral and intravenous MDZ areas under the plasma concentration-time curves were significantly increased by RTV or NFV and were decreased by rifampin. Irrespective of method of administration, RTV decreased net intestinal and hepatic CYP3A activity, whereas NFV decreased hepatic but not intestinal CYP3A activity. The magnitude of these DDIs was more accurately predicted using PI CYP3A inactivation parameters generated in sandwich-cultured human hepatocytes rather than human liver microsomes.
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Innate immunity in the pathogenesis of psoriasis.
Arch. Dermatol. Res.
PUBLISHED: 03-08-2011
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Psoriasis is a common, immune-mediated inflammatory skin disorder. T helper(h)1 and Th17 lymphocytes contribute to the pathogenesis of psoriasis through the release of inflammatory cytokines that promote further recruitment of immune cells, keratinocyte proliferation and sustained inflammation. The innate immune system is the first line of defence against infection and plays a crucial role in the initiation of the adaptive immune response. The presence of innate immune cells and their products in psoriatic skin plaques suggests a role for innate immunity in this disease. In addition, the innate immune system can direct the development of pathogenic Th cells in psoriasis. In this article, we will summarise the role of the innate immune system in psoriasis with particular emphasis on the role of cytokines, signalling pathways and cells of the innate immune system.
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Molecular genetic models related to schizophrenia and psychotic illness: heuristics and challenges.
Curr Top Behav Neurosci
PUBLISHED: 02-08-2011
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Schizophrenia is a heritable disorder that may involve several common genes of small effect and/or rare copy number variation, with phenotypic heterogeneity across patients. Furthermore, any boundaries vis-à-vis other psychotic disorders are far from clear. Consequently, identification of informative animal models for this disorder, which typically relate to pharmacological and putative pathophysiological processes of uncertain validity, faces considerable challenges. In juxtaposition, the majority of mutant models for schizophrenia relate to the functional roles of a diverse set of genes associated with risk for the disorder or with such putative pathophysiological processes. This chapter seeks to outline the evidence from phenotypic studies in mutant models related to schizophrenia. These have commonly assessed the degree to which mutation of a schizophrenia-related gene is associated with the expression of several aspects of the schizophrenia phenotype or more circumscribed, schizophrenia-related endophenotypes; typically, they place specific emphasis on positive and negative symptoms and cognitive deficits, and extend to structural and other pathological features. We first consider the primary technological approaches to the generation of such mutants, to include their relative merits and demerits, and then highlight the diverse phenotypic approaches that have been developed for their assessment. The chapter then considers the application of mutant phenotypes to study pathobiological and pharmacological mechanisms thought to be relevant for schizophrenia, particularly in terms of dopaminergic and glutamatergic dysfunction, and to an increasing range of candidate susceptibility genes and copy number variants. Finally, we discuss several pertinent issues and challenges within the field which relate to both phenotypic evaluation and a growing appreciation of the functional genomics of schizophrenia and the involvement of gene?×?environment interactions.
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Stiffness of photocrosslinked RGD-alginate gels regulates adipose progenitor cell behavior.
Biotechnol. Bioeng.
PUBLISHED: 01-17-2011
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Adipose progenitor cells (APCs) are widely investigated for soft tissue reconstruction following tumor resection; however, the long-term success of current approaches is still limited. In order to develop clinically relevant therapies, a better understanding of the role of cell-microenvironment interactions in adipose tissue regeneration is essential. In particular, the effect of extracellular matrix (ECM) mechanics on the regenerative capability of APCs remains to be clarified. We have used artificial ECMs based on photocrosslinkable RGD-alginate to investigate the adipogenic and pro-angiogenic potential of 3T3-L1 preadipocytes as a function of matrix stiffness. These hydrogels allowed us to decouple matrix stiffness from changes in adhesion peptide density or extracellular Ca(2+) concentration and provided a physiologically relevant 3D culture context. Our findings suggest that increased matrix rigidity promotes APC self-renewal and angiogenic capacity, whereas, it inhibits adipose differentiation. Collectively, this study advances our understanding of the role of ECM mechanics in adipose tissue formation and vascularization and will aid in the design of efficacious biomaterial scaffolds for adipose tissue engineering applications.
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Development of a preliminary composite disease activity index in psoriatic arthritis.
Ann. Rheum. Dis.
PUBLISHED: 11-29-2010
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To develop a preliminary composite psoriatic disease activity index (CPDAI) for psoriasis and psoriatic arthritis.
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Meta-analysis confirms the LCE3C_LCE3B deletion as a risk factor for psoriasis in several ethnic groups and finds interaction with HLA-Cw6.
J. Invest. Dermatol.
PUBLISHED: 11-25-2010
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A multicenter meta-analysis including data from 9,389 psoriasis patients and 9,477 control subjects was performed to investigate the contribution of the deletion of genes LCE3C and LCE3B, involved in skin barrier defense, to psoriasis susceptibility in different populations. The study confirms that the deletion of LCE3C and LCE3B is a common genetic factor for susceptibility to psoriasis in the European populations (OR(Overall) = 1.21 (1.15-1.27)), and for the first time directly demonstrates the deletions association with psoriasis in the Chinese (OR = 1.27 (1.16-1.34)) and Mongolian (OR = 2.08 (1.44-2.99)) populations. The analysis of the HLA-Cw6 locus showed significant differences in the epistatic interaction with the LCE3C and LCE3B deletion in at least some European populations, indicating epistatic effects between these two major genetic contributors to psoriasis. The study highlights the value of examining genetic risk factors in multiple populations to identify genetic interactions, and indicates the need of further studies to understand the interaction of the skin barrier and the immune system in susceptibility to psoriasis.
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Investigation of the interaction of biodegradable micro- and nanoparticulate drug delivery systems with platelets.
J. Pharm. Pharmacol.
PUBLISHED: 11-16-2010
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Biodegradable micro- and nanoparticles are being increasingly investigated for drug delivery and targeting of therapeutics. The size and surface properties of these particles are important factors influencing their interaction and uptake by various cells, tissues and organs. Optimising these properties, to enhance cellular uptake, may increase their potential for interaction with other physiological components such as platelets resulting in platelet activation and inappropriate thrombus formation. The aim of this study was to investigate the potential interaction of particulates with platelets.
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Electrothermal flow effects in insulating (electrodeless) dielectrophoresis systems.
Electrophoresis
PUBLISHED: 11-16-2010
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We simulate electrothermally induced flow in polymeric, insulator-based dielectrophoresis (iDEP) systems with DC-offset, AC electric fields at finite thermal Péclet number, and we identify key regimes where electrothermal (ET) effects enhance particle deflection and trapping. We study a single, two-dimensional constriction in channel depth with parametric variations in electric field, channel geometry, fluid conductivity, particle electrophoretic (EP) mobility, and channel electroosmotic (EO) mobility. We report the effects of increasing particle EP mobility, channel EO mobility, and AC and DC field magnitudes on the mean constriction temperature and particle behavior. Specifically, we quantify particle deflection and trapping, referring to the deviation of particles from their pathlines due to dielectrophoresis as they pass a constriction and the stagnation of particles due to negative dielectrophoresis near a constriction, respectively. This work includes the coupling between fluid, heat, and electromagnetic phenomena via temperature-dependent physical parameters. Results indicate that the temperature distribution depends strongly on the fluid conductivity and electric field magnitude, and particle deflection and trapping depend strongly on the channel geometry. Electrothermal (ET) effects perturb the EO flow field, creating vorticity near the channel constriction and enhancing the deflection and trapping effects. ET effects alter particle deflection and trapping responses in insulator-based dielectrophoresis devices, especially at intermediate device aspect ratios (2 ? r ? 7) in solutions of higher conductivity (? m ? 1 × 10(-3)S/m). The impact of ET effects on particle deflection and trapping are diminished when particle EP mobility or channel EO mobility is high. In almost all cases, ET effects enhance negative dielectrophoretic particle deflection and trapping phenomena.
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Methods for photocrosslinking alginate hydrogel scaffolds with high cell viability.
Tissue Eng Part C Methods
PUBLISHED: 11-04-2010
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Methods for seeding high-viability (>85%) three-dimensional (3D) alginate-chondrocyte hydrogel scaffolds are presented that employ photocrosslinking of methacrylate-modified alginate with the photoinitiator VA-086. Comparison with results from several other photoinitiators, including Irgacure 2959, highlights the role of solvent, ultraviolet exposure, and photoinitiator cytotoxicity on process viability of bovine chondrocytes in two-dimensional culture. The radicals generated from VA-086 photodissociation are shown to be noncytotoxic at w/v concentrations up to 1.5%, enabling photocrosslinking without significant cell death. The applicability of these photoinitiators for generating 3D tissue-engineered constructs is evaluated by measuring cell viability in 3D constructs with aggregate moduli in the 10-20?kPa range. Hydrogels with encapsulated bovine chondrocytes were constructed with >85% viability using VA-086. While the commonly used Irgacure 2959 is noncytotoxic in its native state and crosslinks the alginate at weight fractions much lower than VA-086, the cytotoxicity of IRG2959s photogenerated radical leads to viabilities below 70% in the conditions tested.
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Organising pneumonia associated with fumaric acid ester treatment for psoriasis.
Clin Respir J
PUBLISHED: 10-05-2010
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? We present the case of a 49-year old male who presented with dyspnoea, cough, weight loss, night sweats and general malaise. He had been on treatment with oral fumaric acid esters (FAE, Fumaderm®; Biogen Idec GmbH, Ismaning, Germany) for 6 months.
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Impact of ignoring extraction ratio when predicting drug-drug interactions, fraction metabolized, and intestinal first-pass contribution.
Drug Metab. Dispos.
PUBLISHED: 08-19-2010
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Many mathematical models for in vitro to in vivo prediction of drug-drug interactions (DDIs) of orally administered victim drugs have been developed. However, to date, none of these models have been applicable to all intravenously administered victim drugs. We derived and conducted a sensitivity/error analysis of a modification to the existing multiple mode interaction prediction model such that it is applicable to all intravenously administered victim drugs. Using this model we showed that ignoring the hepatic extraction ratio (EH) (as low as 0.3) of intravenously administered victim drugs can result in 1) substantial underestimation of f(m, CYPi) (the fraction of hepatic clearance of the victim drug via a given enzymatic pathway) and 2) error in dissecting the contribution of intestinal and hepatic components of DDIs for orally administered drugs. Using this model we describe DDI boundaries (degree of inhibition or induction) at which ignoring the EH of commonly used victim drugs results in ?30% error in the predicted area under the concentration-time curve (AUC) ratio or contribution of intestinal interaction to a DDI (CYP3A probes only). For the most widely used victim drug midazolam, these boundaries for AUC ratio are net inhibition (I/K(i) or ?/k(deg)) ?1.3 or fold induction ?2.1; for intestinal contribution the boundaries are 0.37 and 1.5, respectively. To accurately predict the intravenous AUC ratio, intestinal contribution, or f(m, CYPi) 1) for all induction DDIs irrespective of EH of the victim drug and 2) for modest to potent inhibition DDIs even when the EH is moderate (?0.3), we propose that our model be used.
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The effect of narrowband UV-B treatment for psoriasis on vitamin D status during wintertime in Ireland.
Arch Dermatol
PUBLISHED: 08-18-2010
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To determine whether narrowband UV-B (NB-UV-B) may mediate its beneficial effect on psoriasis by increasing vitamin D levels, and to assess the effect of NB-UV-B on vitamin D status in patients with psoriasis in wintertime.
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Cardiovascular disease and risk factors in patients with psoriasis and psoriatic arthritis.
J. Rheumatol.
PUBLISHED: 05-15-2010
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Patients with psoriasis and psoriatic arthritis (PsA) have an increased incidence of cardiovascular disease (CVD) and cardiovascular risk factors such as smoking, hypertension, and metabolic syndrome compared to the normal population. Patients with psoriasis and PsA may also have increased risk from nonconventional risk factors such as raised levels of homocysteine and excessive alcohol consumption. We conducted a comprehensive review of the literature on CVD and all cardiovascular risk factors in patients with psoriasis and PsA.
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NMDA-induced injury of mouse organotypic hippocampal slice cultures triggers delayed neuroblast proliferation in the dentate gyrus: an in vitro model for the study of neural precursor cell proliferation.
Brain Res.
PUBLISHED: 05-03-2010
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We present a model for the study of injury-induced neurogenesis in the dentate gyrus (DG) in murine organotypic hippocampal slice cultures (OHCs). A brief exposure of 8-day-old hippocampal slice cultures to the glutamate receptor agonist N-methyl-d-aspartate (NMDA; 20-50µM for 30 min) caused a selective excitotoxic injury in the CA1 subfield of the hippocampus that matured over a period of 24h. The insult resulted in a prominent up-regulation of proliferating nuclei within the OHC dentate gyrus (DG), and a corresponding increase in Ki67/doublecortin double-positive cells in the SGZ of the dentate gyrus. 5-bromo-2-deoxyuridine (BrdU)-labelling of the OHCs for three days subsequent to the NMDA exposure revealed significantly increased BrdU incorporation within the DG (SGZ and GCL) of the hippocampus. Doublecortin immunofluorescence indicated a concurrent up-regulation of neuronal precursor cells specifically in the SGZ and GCL. Significantly increased BrdU incorporation could be detected up to 6-9 days after termination of the NMDA exposure. The model presented here enables easy manipulation and follow-up of injury-induced neuroblast proliferation in the DG that is amenable to the study of transgenic mice.
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A genome-wide association study identifies new psoriasis susceptibility loci and an interaction between HLA-C and ERAP1.
Nat. Genet.
PUBLISHED: 03-30-2010
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To identify new susceptibility loci for psoriasis, we undertook a genome-wide association study of 594,224 SNPs in 2,622 individuals with psoriasis and 5,667 controls. We identified associations at eight previously unreported genomic loci. Seven loci harbored genes with recognized immune functions (IL28RA, REL, IFIH1, ERAP1, TRAF3IP2, NFKBIA and TYK2). These associations were replicated in 9,079 European samples (six loci with a combined P < 5 × 10?? and two loci with a combined P < 5 × 10??). We also report compelling evidence for an interaction between the HLA-C and ERAP1 loci (combined P = 6.95 × 10??). ERAP1 plays an important role in MHC class I peptide processing. ERAP1 variants only influenced psoriasis susceptibility in individuals carrying the HLA-C risk allele. Our findings implicate pathways that integrate epidermal barrier dysfunction with innate and adaptive immune dysregulation in psoriasis pathogenesis.
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Mutant mouse models: genotype-phenotype relationships to negative symptoms in schizophrenia.
Schizophr Bull
PUBLISHED: 11-24-2009
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Negative symptoms encompass diminution in emotional expression and motivation, some of which relate to human attributes that may not be accessible readily in animals. Additionally, their refractoriness to treatment precludes therapeutic validation of putative models. This review considers critically the application of mutant mouse models to the study of the pathobiology of negative symptoms. It focuses on 4 main approaches: genes related to the pathobiology of schizophrenia, genes associated with risk for schizophrenia, neurodevelopmental-synaptic genes, and variant approaches from other areas of neurobiology. Despite rapid advances over the past several years, it is clear that we continue to face substantive challenges in applying mutant models to better understand the pathobiology of negative symptoms: the majority of evidence relates to impairments in social behavior, with only limited data relating to anhedonia and negligible data concerning avolition and other features; even for the most widely examined feature, social behavior, studies have used diverse assessments thereof; modelling must proceed in cognizance of increasing evidence that genes and pathobiologies implicated in schizophrenia overlap with other psychotic disorders, particularly bipolar disorder. Despite the caveats and challenges, several mutant lines evidence a phenotype for at least one index of social behavior. Though this may suggest superficially some shared relationship to negative symptoms, it is not yet possible to specify either the scope or the pathobiology of that relationship for any given gene. The breadth and depth of ongoing studies in mutants hold the prospect of addressing these shortcomings.
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Capture of circulating tumor cells from whole blood of prostate cancer patients using geometrically enhanced differential immunocapture (GEDI) and a prostate-specific antibody.
Lab Chip
PUBLISHED: 11-16-2009
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Geometrically enhanced differential immunocapture (GEDI) and an antibody for prostate-specific membrane antigen (PSMA) are used for high-efficiency and high-purity capture of prostate circulating tumor cells from peripheral whole blood samples of castrate-resistant prostate cancer patients.
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Transient zeta-potential measurements in hydrophobic, TOPAS microfluidic substrates.
Electrophoresis
PUBLISHED: 07-29-2009
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We utilize time-resolved electrokinetic measurements in order to study the electrokinetic properties of silica and TOPAS microfluidic channels as a function of the time history of the fluid-solid interface. In pressure-driven flow through TOPAS microchannels, the zeta-potential as inferred from streaming potential measurements decays exponentially by a factor of 1.5 with a characteristic decay time of 3 h after the initial formation of the fluid-solid interface. A similar exponential decay is observed immediately after water is exchanged for ethanol as the solvent in the system. In electroosmotically driven flow through TOPAS microchannels, the zeta-potential as inferred through current monitoring experiments was constant in time. No electrokinetic transients were observed in silica microchannels under these flow conditions.
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Advancing a functional genomics for schizophrenia: psychopathological and cognitive phenotypes in mutants with gene disruption.
Brain Res. Bull.
PUBLISHED: 04-19-2009
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Schizophrenia is a complex, heritable psychotic disorder in which numerous genes and environmental adversities appear to interact in determining disease phenotype. In addition to genes regulating putative pathophysiological mechanisms, a new generation of molecular studies has indicated numerous candidate genes to be associated with risk for schizophrenia. The present review focuses on studies in mice mutant for genes associated with putative pathophysiological mechanisms and candidate risk genes for the disorder. It seeks to evaluate the extent to which each mutation of a schizophrenia-related gene accurately models multiple aspects of the schizophrenia phenotype or more circumscribed, distinct endophenotypes in terms of psychopathology and pathobiology; in doing so, it places particular emphasis on positive symptoms, negative symptoms and cognitive dysfunction. To further this goal, it juxtaposes continually evolving mutant genomics with emergent clinical genomic studies. Opportunities and challenges associated with the use of such mutants, including diagnostic specificity and the translational barrier associated with modelling schizophrenia, are discussed. The potential value of genetic models for exploring gene-gene and gene-environment interactions relating to schizophrenia is highlighted. Elucidation of the contribution of genetic variation to specific symptom clusters and underlying aspects of pathobiology will have important implications for identifying treatments that target distinct domains of psychopathology and dysfunction on an individual patient basis.
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Medial prefrontal cortex lesions in mice do not impair effort-based decision making.
Neuropharmacology
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The function of the medial prefrontal cortex has previously been determined in the rat to play an important role in effort-based decision making and this, along with functions of other areas, has been assumed largely, to hold true in all rodents. In this study, we attempted to replicate this result in mice and to develop a model for effort-based decision making that could be useful for the study of neurological conditions. Mice were trained on a cost-benefit T-maze paradigm, whereby they chose between a low reward with little effort needed to obtain it or a higher reward, which required increased effort. Following training, the medial prefrontal cortex was lesioned. After surgery, contrary to earlier published rat studies, the performance of the mice did not change. In previous studies, prefrontal cortex lesioned rats chose the low effort/low reward option, but lesioned mice continued to select the high reward/high effort option. However, the other results are in line with previous mouse studies in both the extent of pathology and anxiety-like behaviour. These results illustrate a difference in the functioning of the prefrontal cortex between rats and mice and offer a word of caution on the interpretation of data from studies that employ different species.
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Isolation and characterization of circulating tumor cells in prostate cancer.
Front Oncol
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Circulating tumor cells (CTCs) are tumor cells found in the peripheral blood that putatively originate from established sites of malignancy and likely have metastatic potential. Analysis of CTCs has demonstrated promise as a prognostic marker as well as a source of identifying potential targets for novel therapeutics. Isolation and characterization of these cells for study, however, remain challenging owing to their rarity in comparison with other cellular components of the peripheral blood. Several techniques that exploit the unique biochemical properties of CTCs have been developed to facilitate their isolation. Positive selection of CTCs has been achieved using microfluidic surfaces coated with antibodies against epithelial cell markers or tumor-specific antigens such as EpCAM or prostate-specific membrane antigen (PSMA). Following isolation, characterization of CTCs may help guide clinical decision making. For instance, molecular and genetic characterization may shed light on the development of chemotherapy resistance and mechanisms of metastasis without the need for a tissue biopsy. This paper will review novel isolation techniques to capture CTCs from patients with advanced prostate cancer, as well as efforts to characterize the CTCs. We will also review how these analyzes can assist in clinical decision making. Conclusion: The study of CTCs provides insight into the molecular biology of tumors of prostate origin that will eventually guide the development of tailored therapeutics. These advances are predicated on high yield and accurate isolation techniques that exploit the unique biochemical features of these cells.
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Microfluidic transport in microdevices for rare cell capture.
Electrophoresis
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The isolation and capture of rare cells is a problem uniquely suited to microfluidic devices, in which geometries on the cellular length scale can be engineered and a wide range of chemical functionalizations can be implemented. The performance of such devices is primarily affected by the chemical interaction between the cell and the capture surface and the mechanics of cell-surface collision and adhesion. As rare cell-capture technology has been summarized elsewhere (E. D. Pratt et al., Chem. Eng. Sci. 2011, 66, 1508-1522), this article focuses on the fundamental adhesion and transport mechanisms in rare cell-capture microdevices, and explores modern device design strategies in a transport context. The biorheology and engineering parameters of cell adhesion are defined; adhesion models and reaction kinetics briefly reviewed. Transport at the microscale, including diffusion and steric interactions that result in cell motion across streamlines, is discussed. The review concludes by discussing design strategies with a focus on leveraging the underlying transport phenomena to maximize device performance.
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High prevalence of psoriatic arthritis in patients with severe psoriasis with suboptimal performance of screening questionnaires.
Ann. Rheum. Dis.
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The objectives of this study were to: (1) assess the prevalence of psoriatic arthritis (PsA) among Psoriasis (Ps) patients attending dermatology clinics; (2) identify clinical predictors of the development of PsA; and (3) compare the performance of three PsA screening questionnaires: Psoriatic Arthritis Screening and Evaluation (PASE), Psoriasis Epidemiology Screening Tool (PEST) and Toronto Psoriatic Arthritis Screening (ToPAS).
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Evaluation of P450 inhibition and induction by artemisinin antimalarials in human liver microsomes and primary human hepatocytes.
Drug Metab. Dispos.
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Artemisinin drugs have become the first-line antimalarials in areas of multidrug resistance. However, monotherapy with artemisinin drugs results in comparatively high recrudescence rates. Autoinduction of cytochrome P450 (P450)-mediated metabolism, resulting in reduced exposure, has been supposed to be the underlying mechanism. To better understand the autoinduction and metabolic drug-drug interactions (DDIs), we evaluated the P450s (particularly CYP2B6 and CYP3A4) inhibited or induced by two artemisinin drugs, Qing-hao-su (QHS) and dihydroartemisinin (DHA) using human liver microsome, recombinant P450 enzymes, and primary human hepatocytes. The results suggested that QHS was a weak reversible inhibitor of CYP2B6 (K(i) 4.6 ?M), but not CYP3A4 (IC?? ? 50 ?M) and did not show measurable time-dependent inhibition of either CYP2B6 or CYP3A4. DHA inhibited neither CYP2B6 nor CYP3A4 (IC?? > 125 ?M). In addition, it was found that QHS induced the activity of CYP3A4 (E(max) 3.5-fold and EC?? 5.9 ?M) and CYP2B6 (E(max) 1.9-fold and EC?? 0.6 ?M). Of the other P450s, UDP glucuronosyltransferases, and transporters studied, QHS and DHA had no significant effect except for minor induction of mRNA expression of CYP1A2 (E(max) 7.9-fold and EC?? 5.2 ?M) and CYP2A6 (E(max) 11.7-fold and EC?? 4.0 ?M) by QHS. Quantitative prediction of P450-mediated DDIs indicate autoinduction of QHS clearance with the AUC(i)/AUC ratio decreasing to 59%, as a result of a 1.9-fold increase in CYP3A4 and a 1.6-fold increase in CYP2B6 activity. These data suggest that QHS drugs are potential inducers of P450 enzymes, and the possible drug interactions (or lack thereof) with artemisinin drugs may be clinically relevant.
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Functional characterization of circulating tumor cells with a prostate-cancer-specific microfluidic device.
PLoS ONE
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Cancer metastasis accounts for the majority of cancer-related deaths owing to poor response to anticancer therapies. Molecular understanding of metastasis-associated drug resistance remains elusive due to the scarcity of available tumor tissue. Isolation of circulating tumor cells (CTCs) from the peripheral blood of patients has emerged as a valid alternative source of tumor tissue that can be subjected to molecular characterization. However, issues with low purity and sensitivity have impeded adoption to clinical practice. Here we report a novel method to capture and molecularly characterize CTCs isolated from castrate-resistant prostate cancer patients (CRPC) receiving taxane chemotherapy. We have developed a geometrically enhanced differential immunocapture (GEDI) microfluidic device that combines an anti-prostate specific membrane antigen (PSMA) antibody with a 3D geometry that captures CTCs while minimizing nonspecific leukocyte adhesion. Enumeration of GEDI-captured CTCs (defined as intact, nucleated PSMA+/CD45- cells) revealed a median of 54 cells per ml identified in CRPC patients versus 3 in healthy donors. Direct comparison with the commercially available CellSearch® revealed a 2-400 fold higher sensitivity achieved with the GEDI device. Confocal microscopy of patient-derived GEDI-captured CTCs identified the TMPRSS2:ERG fusion protein, while sequencing identified specific androgen receptor point mutation (T868A) in blood samples spiked with only 50 PC C4-2 cells. On-chip treatment of patient-derived CTCs with docetaxel and paclitaxel allowed monitoring of drug-target engagement by means of microtubule bundling. CTCs isolated from docetaxel-resistant CRPC patients did not show any evidence of drug activity. These measurements constitute the first functional assays of drug-target engagement in living circulating tumor cells and therefore have the potential to enable longitudinal monitoring of target response and inform the development of new anticancer agents.
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Quantification of human hepatocyte cytochrome P450 enzymes and transporters induced by HIV protease inhibitors using newly validated LC-MS/MS cocktail assays and RT-PCR.
Biopharm Drug Dispos
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Human immunodeficiency virus (HIV) protease inhibitors (PIs) produce profound and unpredictable drug-drug interactions (DDIs) that cannot be explained fully by their inhibition/inactivation of CYP3A enzymes. Delineating and quantifying the CYPs and transporters inducible by PIs are crucial in developing an integrative mechanistic understanding and prediction of PI-based DDIs. To do so, two LC-MS/MS cocktail assays were modified and validated simultaneously to quantify the CYP activity of CYP3A, 2B6, 2C8, 2C9, 2C19, 1A, 2E1, 2A6 and 2D6 enzymes. These new assays were applied to evaluate the induction potential of eight PIs in microsomes isolated from PI-treated human hepatocytes. The mRNA expression of these CYPs and transporters (OATP1B1, OATP1B3, OATP1A2, MDR1, MRP2 and MRP4) was also evaluated using relative RT-PCR. The majority of PIs were net inducers of CYP3As and 2B6 at both the mRNA and activity level (> 2-fold), while ritonavir, saquinavir, nelfinavir or lopinavir did not induce CYP3A activity (< 2-fold), presumably due to CYP3A inactivation. OATP1B1 and MDR1 were the only two hepatic transporters induced (> 2-fold) by the PIs. Amprenavir was the most potent net inducer. In conclusion, our validated cocktail assays can be implemented to comprehensively quantify CYP activities in human liver microsomes and hepatocyte studies. The results also provide the much needed data on the net induction potential of the PIs for hepatic CYPs and transporters. A qualitative agreement was observed between our results and published PI-based DDIs, suggesting that human hepatocytes are a useful platform for more extensive and quantitative in vitro-in vivo prediction of PI-based DDIs.
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Notch-1 mediates endothelial cell activation and invasion in Psoriasis.
Exp. Dermatol.
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Notch-receptor-ligand interactions are critical for cell proliferation, differentiation and survival, however the role of Notch signalling in psoriasis remains to be elucidated. Serum amyloid A (A-SAA) is an acute-phase protein with cytokine-like properties, regulates cell survival pathways and is implicated in many inflammatory conditions.
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Parametric control of collision rates and capture rates in geometrically enhanced differential immunocapture (GEDI) microfluidic devices for rare cell capture.
Biomed Microdevices
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The enrichment and isolation of rare cells from complex samples, such as circulating tumor cells (CTCs) from whole blood, is an important engineering problem with widespread clinical applications. One approach uses a microfluidic obstacle array with an antibody surface functionalization to both guide cells into contact with the capture surface and to facilitate adhesion; geometrically enhanced differential immunocapture is a design strategy in which the array is designed to promote target cell-obstacle contact and minimize other interactions (Gleghorn et al. 2010; Kirby et al. 2012). We present a simulation that uses capture experiments in a simple Hele-Shaw geometry (Santana et al. 2012) to inform a target-cell-specific capture model that can predict capture probability in immunocapture microdevices of any arbitrary complex geometry. We show that capture performance is strongly dependent on the array geometry, and that it is possible to select an obstacle array geometry that maximizes capture efficiency (by creating combinations of frequent target cell-obstacle collisions and shear stress low enough to support capture), while simultaneously enhancing purity by minimizing non-specific adhesion of both smaller contaminant cells (with infrequent cell-obstacle collisions) and larger contaminant cells (by focusing those collisions into regions of high shear stress).
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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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.