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Viable
Terms modified by Viable Selected AbstractsDielectrophoresis microsystem with integrated flow cytometers for on-line monitoring of sorting efficiencyELECTROPHORESIS, Issue 24 2006Zhenyu Wang Abstract Dielectrophoresis (DEP) and flow cytometry are powerful technologies and widely applied in microfluidic systems for handling and measuring cells and particles. Here, we present a novel microchip with a DEP selective filter integrated with two microchip flow cytometers (FCs) for on-line monitoring of cell sorting processes. On the microchip, the DEP filter is integrated in a microfluidic channel network to sort yeast cells by positive DEP. The two FCs detection windows are set upstream and downstream of the DEP filter. When a cell passes through the detection windows, the light scattered by the cell is measured by integrated polymer optical elements (waveguide, lens, and fiber coupler). By comparing the cell counting rates measured by the two FCs, the collection efficiency of the DEP filter can be determined. The chips were used for quantitative determination of the effect of flow rate, applied voltage, conductivity of the sample, and frequency of the electric field on the sorting efficiency. A theoretical model for the capture efficiency was developed and a reasonable agreement with the experimental results observed. Viable and non-viable yeast cells showed different frequency dependencies and were sorted with high efficiency. At 2,MHz, more than 90% of the viable and less than 10% of the non-viable cells were captured on the DEP filter. The presented approach provides quantitative real-time data for sorting a large number of cells and will allow optimization of the conditions for, e.g., collecting cancer cells on a DEP filter while normal cells pass through the system. Furthermore, the microstructure is simple to fabricate and can easily be integrated with other microstructures for lab-on-a-chip applications. [source] A Chemical Approach Towards Understanding the Mechanism and Reversal of Drug Resistance in Plasmodium falciparum: Is it Viable?IUBMB LIFE, Issue 4-5 2002Kelly Chibale Abstract Genetic and biochemical approaches to studies of drug resistance mechanisms in Plasmodium falciparum have raised controversies and contradictions over the past several years. A different and novel chemical approach to this important problem is desirable at this point in time. Recently, the molecular basis of drug resistance in P. falciparum has been associated with mutations in the resistance genes, Chloroquine Resistance Transporter (PfCRT) and the P-glycoprotein homologue (Pgh1). Although not the determinant of chloroquine resistance in P. falciparum, mutations in Pgh1 have important implications for resistance to other antimalarial drugs. Because it is mutations in the aforementioned resistance genes rather than overexpression that has been associated with drug resistance in malaria, studies on mechanisms of drug resistance and its reversal by chemosensitisers should benefit from a chemical approach. Target-oriented organic synthesis of chemosensitisers against proteins implicated in drug resistance in malaria should shed light on mechanism of drug resistance and its reversal in this area. The effect of structurally diverse chemosensitisers should be examined on several putative resistance genes in P. falciparum to deal with antimalarial drug resistance in the broadest sense. Therefore, generating random mutations of these resistance proteins and subsequent screening in search of a specific phenotype followed by a search for mutations and/or chemosensitisers that affect a specific drug resistance pathway might be a viable strategy. This diversity-oriented organic synthesis approach should offer the means to simultaneously identify resistance proteins that can serve as targets for therapeutic intervention (therapeutic target validation) and chemosensitisers that modulate the functions of these proteins (chemical target validation). [source] Viable but non-culturable Listeria monocytogenes on parsley leaves and absence of recovery to a culturable stateJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2007N. Dreux Abstract Aims:, To investigate the presence of viable but non-culturable Listeria monocytogenes during survival on parsley leaves under low relative humidity (RH) and to evaluate the ability of L. monocytogenes to recover from VBNC to culturable state under satured humidity. Methods and Results:, Under low RH (47,69%) on parsley leaves, the initial number of L. monocytogenes populations counted on non selective media (109 L. monocytogenes per leaf on TSA) was reduced by 6 log10 scales in 15 days, whereas number of viable L. monocytogenes counted under the microscope was reduced by 3,4 log10 scales, indicating the presence of VBNC cells. This was demonstrated on three L. monocytogenes strains (EGDe, Bug 1995 and LmP60). Changing from low to 100% RH permitted an increase of the culturable counts of L. monocytogenes and this growth was observed only when residual culturable cells were present. Moreover, VBNC L. monocytogenes inoculated on parsley leaves did not become culturable after incubation under 100% RH. Conclusions:, Dry conditions induced VBNC L. monocytogenes on parsley leaves but these VBNC were likely unable to recover culturability after transfer to satured humidity. Significance and Impact of Study:, Enumeration on culture media presumably under-estimates the number of viable L. monocytogenes on fresh produce after exposure to low RH. [source] Unsuitable distinction between viable and dead Staphylococcus aureus and Staphylococcus epidermidis by ethidium bromide monoazideLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2009H. Kobayashi Abstract Aims:, The DNA-intercalating dye ethidium bromide monoazide (EMA) has recently been used as a DNA binding agent to differentiate viable and dead bacterial cells by selectively penetrating through the damaged membrane of dead cells and blocking the DNA amplification during the polymerase chain reaction (PCR). We optimized and tested the assay in vitro using Staphylococcus aureus and Staphylococcus epidermidis cultures to distinguish viable from dead bacteria, with the goal of reducing false positive PCR results. Methods and Results:, Viable and heat-inactivated bacteria were treated with EMA or left untreated before DNA extraction. A real-time PCR assay for the detection of the tuf gene in each DNA extract was used. Our results indicated that EMA influenced viable bacteria as well as dead bacteria, and the effect of EMA depended on the EMA concentration and bacterial number. Conclusions:, EMA is not a suitable indicator of bacterial viability, at least with respect to Staphylococcus species. Significance and Impact of the Study:, Determining the viability of pathogens has a major impact on interpreting the results of molecular tests for bacteria and subsequent clinical management of patients. To this end, several methods are being evaluated. One of these methods , intercalating DNA of dead bacteria by EMA , looked very promising, but our study found it unsatisfactory for S. aureus and coagulase-negative Staphylococci. [source] Is a Two-State Solution Still Viable?MIDDLE EAST POLICY, Issue 2 2003Stephen P. Cohen The following is an edited transcript of the thirty-second in a series of Capitol Hill conferences convened by the Middle East Policy Council. The meeting was held on April 11, 2003, in the Dirksen Senate Office Building with Chas. W. Freeman, Jr., moderating. [source] Comparison of ion transportation before and after egg hatching in Amphinemura sp. (Plecoptera)PHYSIOLOGICAL ENTOMOLOGY, Issue 4 2006MAYUMI YOSHIMURA Abstract An increase in egg size with embryonic development in stoneflies is believed to result from the uptake of water by osmosis. The present study aims to investigate whether a selective ion transport through egg membranes exists before hatching, and whether ions are released after hatching. Viable and nonviable egg masses are incubated in Petri dishes filled with water, and the concentrations of the ions F,, Cl,, SO42,, NO3,, Na+, K,, Mg2+ and Ca2+ in the water are determined. The ion transport of an egg mass before and after hatching and a nonviable egg mass is then calculated. Before hatching, Cl,, SO42,, NO3,, Na+, Mg2+ and Ca2+ are taken up from the surrounding water into the inner egg. These ions are selectively taken into the egg. After hatching, Cl,, SO42,, Na+, Mg2+ and Ca2+ are released into the surrounding water. The amount of these ions released after hatching is lower than the amount taken up before hatching. Ions that are not released after hatching are considered to be used in embryonic development. [source] Use of a leucocyte filter to remove tumour cells from intra-operative cell salvage bloodANAESTHESIA, Issue 12 2008S. Catling Summary The intra-operative blood loss of 50 consecutive gynae-oncology patients undergoing surgery for endometrial, cervical or ovarian cancer was cell salvaged and filtered. In each case blood samples were taken from the effluent tumour vein, a central venous line, the cell saver reservoir, the cell salvage re-transfusion bag after processing but before filtration and from the cell salvage re-transfusion bag after processing and filtration. Samples were examined using immunohistochemical monoclonal antibody markers for epithelial cell lines. Viable, nucleated malignant cells were detected in 2/50 central venous samples, 34/50 reservoir samples and 31/50 unfiltered cell salvaged samples. After passage through a Pall RS leucocyte depletion filter no remaining viable, nucleated malignant cells were detected in any sample. The clinical risks of cell salvage in these circumstances should be reviewed in the light of the risks of allogeneic blood transfusion. [source] A Recombinant Bacteriophage-Based Assay for the Discriminative Detection of Culturable and Viable but Nonculturable Escherichia coli O157:H7BIOTECHNOLOGY PROGRESS, Issue 3 2006Raheela Awais A previously green fluorescent protein (GFP)-labeled PP01 virulent bacteriophage, specific to Escherichia coli O157:H7, was used to construct lysozyme-inactivated GFP-labeled PP01 phage (PP01e - /GFP). The new recombinant phage lacked lytic activity because of the inactivation of gene e, which produces the lysozyme responsible for cell lysis. Gene e was inactivated by inserting an amber stop codon. Prolonged incubation ofE. coli O157:H7 cells with PP01e - /GFP did not lead to cell lysis, while the propagation of PP01e - /GFP in host cells increased the intensity of green fluorescence. Retention of cell morphology and increase in fluorescence enabled the direct visualization and enumeration of E. coli O157:H7 cells within an hour. The PP01e - /GFP system, when combined with nutrient uptake analysis, further allowed the discriminative detection of culturable, viable but nonculturable (VBNC), and dead cells in the stress-induced aquatic environment. Stress-induced cells, which retained culturability, allowed phage propagation and produced bright green florescence. Nonculturable cells (VBNC and dead) allowed only phage adsorption but no proliferation and remained low fluorescent. The low-fluorescent nonculturable cells were further differentiated into VBNC and dead cells on the basis of nutrient uptake analysis. The low-fluorescent cells, which grew in size by nutrient incorporation during prolonged incubation in nutrient medium, were defined as metabolically active and in the VBNC state. The elongated VBNC cells were then easily recognizable from dead cells. The proposed assay enabled the detection and quantification of VBNC cells. Additionally, it revealed the proportion of culturable to VBNC cells within the population, as opposed to conventional techniques, which demonstrate VBNC cells as a differential value of the total viable count and the culturable cell count. [source] ChemInform Abstract: Guanidinium Nitrate/Silica Sulfuric Acid/Ammonium Bromide as an Effective, Viable and Metal-Free Catalytic Media for the Selective Oxidation of Sulfides to the Sulfoxides.CHEMINFORM, Issue 19 2010Mohsen Nikoorazm Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Practical CFD Simulations on Programmable Graphics Hardware using SMAC,COMPUTER GRAPHICS FORUM, Issue 4 2005Carlos E. Scheidegger Abstract The explosive growth in integration technology and the parallel nature of rasterization-based graphics APIs (Application Programming Interface) changed the panorama of consumer-level graphics: today, GPUs (Graphics Processing Units) are cheap, fast and ubiquitous. We show how to harness the computational power of GPUs and solve the incompressible Navier-Stokes fluid equations significantly faster (more than one order of magnitude in average) than on CPU solvers of comparable cost. While past approaches typically used Stam's implicit solver, we use a variation of SMAC (Simplified Marker and Cell). SMAC is widely used in engineering applications, where experimental reproducibility is essential. Thus, we show that the GPU is a viable and affordable processor for scientific applications. Our solver works with general rectangular domains (possibly with obstacles), implements a variety of boundary conditions and incorporates energy transport through the traditional Boussinesq approximation. Finally, we discuss the implications of our solver in light of future GPU features, and possible extensions such as three-dimensional domains and free-boundary problems. [source] Social Infrastructure Planning: A Location Model and Solution MethodsCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 8 2007Joăo F. Bigotte Authorities want to determine where to locate the facilities of a social infrastructure network and what should be the capacity of these facilities. Each user must be assigned to its closest facility and, to be economically viable, each facility must serve at least a pre-specified level of demand. The objective is to maximize the accessibility to facilities (i.e., to minimize the distance traveled by users to reach the facilities). A location model that captures the above features is formulated and different solution methods are tested. Among the methods tested, tabu search and a specialized local search heuristic provided the best solutions. The application of the model is illustrated through a case study involving the location of preschools in the municipality of Miranda do Corvo, Portugal. [source] Toward portable nuclear magnetic resonance devices using atomic magnetometersCONCEPTS IN MAGNETIC RESONANCE, Issue 2 2009Dindi Yu Abstract The motivation for developing alternative detection techniques for nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) is to overcome some of the limitations associated with high-field NMR/MRI instruments. The limitations include poor portability, cryogenic requirements, and high costs. To achieve this goal, a low magnetic field is preferred. Since the sensitivity of inductive detection for conventional NMR and MRI scales linearly with the magnetic field strength, it is not optimal for low-field detection. In this contribution, we describe the concept of using atomic magnetometers as an alternative detection method. Atomic magnetometers possess an ultrahigh sensitivity that is independent of the magnetic field strength, which makes them viable for low-field detection in NMR and MRI. We first introduce the principle of atomic magnetometry and follow this with a discussion of recent progress in the field. To compare the sensitivities of atomic magnetometers of diverse sizes, we define a signal-to-noise ratio for a fixed detection volume to normalize the sensitivity with regard to the cell size. We then focus on two coupling schemes for NMR and MRI detection using atomic magnetometers. Finally, we discuss the challenges involved in implementing this alternative detection technique for NMR and MRI. © 2009 Wiley Periodicals, Inc. Concepts Magn Reson Part A 34A: 124,132, 2009. [source] Distributed loop-scheduling schemes for heterogeneous computer systemsCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 7 2006Anthony T. Chronopoulos Abstract Distributed computing systems are a viable and less expensive alternative to parallel computers. However, a serious difficulty in concurrent programming of a distributed system is how to deal with scheduling and load balancing of such a system which may consist of heterogeneous computers. Some distributed scheduling schemes suitable for parallel loops with independent iterations on heterogeneous computer clusters have been designed in the past. In this work we study self-scheduling schemes for parallel loops with independent iterations which have been applied to multiprocessor systems in the past. We extend one important scheme of this type to a distributed version suitable for heterogeneous distributed systems. We implement our new scheme on a network of computers and make performance comparisons with other existing schemes. Copyright © 2005 John Wiley & Sons, Ltd. [source] Identification and authentication of integrated circuitsCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 11 2004Blaise Gassend Abstract This paper describes a technique to reliably and securely identify individual integrated circuits (ICs) based on the precise measurement of circuit delays and a simple challenge,response protocol. This technique could be used to produce key-cards that are more difficult to clone than ones involving digital keys on the IC. We consider potential venues of attack against our system, and present candidate implementations. Experiments on Field Programmable Gate Arrays show that the technique is viable, but that our current implementations could require some strengthening before it can be considered as secure. Copyright © 2004 John Wiley & Sons, Ltd. [source] Commercializing bycatch can push a fishery beyond economic extinctionCONSERVATION LETTERS, Issue 4 2010Aaron Savio Lobo Abstract Tropical bottom trawling is among the most destructive fishing practices, catching large quantities of bycatch, which are usually discarded. We used questionnaire surveys of trawl fishers to look at changes in catches over the last 30 years (1978,2008) along India's Coromandel Coast. We show that catches and income from target species have declined sharply over the last two decades. Meanwhile, costs of fishing have increased substantially and now almost exceed income from target species. Over the same period, bycatch (which was traditionally discarded) has now become increasingly marketable, being sold for local consumption, and as fish meal to supply the region's rapidly growing poultry industry. Without this income from bycatch, the fishery would scarcely be economically viable. While such a change in the use of bycatch is good news in terms of reducing waste and improving livelihoods, it is also responsible for pushing the Indian bottom trawl fishery beyond the economic extinction of its target species. [source] State transitions of Vibrio parahaemolyticus VBNC cells evaluated by flow cytometry,CYTOMETRY, Issue 5 2008Tania Falcioni Abstract Background Vibrio parahaemolyticus, in response to environmental conditions, may be present in a viable but nonculturable state (VBNC), which can still be responsible for cases of infectious diseases in humans. Methods The characterization of the cellular states of V. parahaemolyticus during entry into, persistence in, and resuscitation from the VBNC state, was assessed through plate culture method and epifluorescence microscope evaluation of actively respiring cells. Flow cytometry (FCM) in combination with SYBR Green I (SG) and propidium iodide allowed us to distinguish between viable, dead, and damaged-cells. Immunofluorescence labeling detected by FCM was used to study changes in antibody affinity. Results Two groups of bacteria, one with High Nucleic Acid (HNA) and one having Low Nucleic Acid (LNA) content, were differentiated using SG and FCM and each was correlated with cell viability. With the aging of the microcosm, the LNA bacteria population increased while the HNA population gradually disappeared. Cytofluorimetric immunofluorescence analyses showed that the bacterial cell levels dropped from 95% at day 0 to 40% at day 26 and by day 29, antibody affinity was virtually lost. FCM analyses of light scatter signals expressed by cell population highlighted morphological changes indicating a reduction in cell size, as also shown by scanning electron microscopy images and variations in cell structure. Conclusions The methodology used has provided useful data in relation to the state transitions of V. parahaemolyticus regarding cell viability, antigenic surface components, and the quantification of morphological variations during its entry into the VBNC state. © 2008 Clinical Cytometry Society [source] Prednisone induces immunophenotypic modulation of CD10 and CD34 in nonapoptotic B-cell precursor acute lymphoblastic leukemia cells,CYTOMETRY, Issue 3 2008Giuseppe Gaipa Abstract Background: Immunophenotypic modulation is induced by steroids in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL) patients during remission induction therapy. Methods: We cultured BCP-ALL blasts from diagnostic bone marrow (BM) samples (n = 20) in the presence of prednisone on stroma layer obtained from BM-derived mesenchymal cells to maintain viability. Antigen expression was assessed by multiparametric flow cytometry. Results: Leukemia samples that sustained the treatment in vitro with prednisone, showed significative reduction of CD10 and CD34 expression compared with control, and it was comparable with that observed in residual leukemic cells of the same patients in BM at day 15 of treatment. Modulated cells were viable as determined by Annexin V staining and preserved light scattering properties. Of note, the extent of antigen modulation in vitro correlated with response to prednisone in vivo. Conclusions: The prednisone-induced immunophenotypic modulation can be reproduced in vitro and this phenomenon may reflect sensitivity to chemotherapy. © 2008 Clinical Cytometry Society [source] Flow cytometric measurement of circulating endothelial cells: The effect of age and peripheral arterial disease on baseline levels of mature and progenitor populationsCYTOMETRY, Issue 2 2006Rebecca Gusic Shaffer Abstract Background: Age and cardiovascular disease status appear to alter numbers and function of circulating endothelial progenitor cells (EPCs). Despite no universal phenotypic definition, numerous studies have implicated progenitors with apparent endothelial potential in local responses to vascular injury and with cardiovascular disease in general. To further define the role of this lineage in peripheral artery disease (PAD), we developed a multiparameter flow cytometry assay to analyze multiple phenotypic definitions of progenitor cells (PCs), EPCs, and mature endothelial cells (ECs) and evaluate effects of age and PAD on baseline levels of each subset. Methods: Blood was collected from young healthy subjects (N = 9, mean age 33 ± 8 years), older healthy subjects (N = 13, mean age 66 ± 8 years), and older subjects with PAD (N = 15, mean age 69 ± 8 years). After ammonium chloride lysis, cells were stained and analyzed on a Becton-Dickinson LSR II with a 5-color antibody panel: FITC-anti-CD31, PE-anti-CD146, PE-anti-CD133, PerCP-Cy5.5-anti-CD3,-CD19,-CD33 (lineage panel), PE-Cy7-anti-CD34, and APC-anti-VEGF-R2. Viability was assessed by propidium iodide exclusion, and only viable, low to medium side scatter lineage-negative singlets were analyzed. In some studies, cells were sorted for morphological studies. Subsets were defined as indicated later. Results: Our results, using a comprehensive flow cytometric panel, indicate that CD133+, CD34+, and CD133+/CD34+ PCs are elevated in younger healthy individuals compared to older individuals, both healthy and with PAD. However, the number of EPCs and mature ECs did not significantly differ among the three groups. Assessment of endothelial colony forming units and dual acLDL-lectin staining supported the flow cytometric findings. Conclusions: We describe a comprehensive flow cytometric method to detect circulating mature and progenitor endothelial populations confirmed by conventional morphological and functional assays. Our findings suggest that aging may influence circulating levels of PCs, but not EPCs or ECs; PAD had no effect on baseline levels of any populations investigated. This study provides the basis for evaluating the potential effects of acute stress and therapeutic intervention on circulating progenitor and endothelial populations as a biomarker for cardiovascular status. © 2005 International Society for Analytical Cytology [source] Single-cell image analysis to assess ABC-transporter,mediated efflux in highly purified hematopoietic progenitorsCYTOMETRY, Issue 4 2002H.G.P. Raaijmakers Abstract Background Normal and malignant hematopoietic stem cells are characterized by their capacity to actively extrude fluorescent dyes. The contribution of different ATP-binding cassette (ABC) transporters to this phenomenon is largely unknown due to the small stem cell numbers limiting the use of standard methods to assess functional efflux. Methods We used epifluorescence microscopy (EFM) in combination with single-cell image analysis to study ABC-transporter,mediated efflux in highly purified, viable, CD34+CD38- cells sorted on an adhesive biolayer. P-glycoprotein and multidrug-resistant protein (MRP)-mediated efflux were quantitated using fluorescent substrates (rhodamine-123 and calcein acetoxymethyl ester [calcein-AM]) and specific inhibitors (verapamil and probenecid, respectively). Results The feasibility, sensitivity, and reproducibility of rhodamine-123 efflux quantitation using single-cell EFM was shown in cell lines and compared with standard flow cytometric assessment. P-glycoprotein,mediated transport was higher in CD34+CD38- cells than in more differentiated progenitors (mean efflux index = 2.24 ± 0.35 and 1.14 ± 0.11, respectively; P = 0.01). P-glycoprotein,mediated transport was the main determinant of the rhodamine "dull" phenotype of these cells. In addition, significant MRP-mediated efflux was demonstrated in CD34+CD38- and CD38+ cells (mean efflux index = 1.42 ± 0.19 and 1.28 ± 0.18, respectively). Conclusion The described method is a valuable tool for assessing ABC-transporter,mediated efflux in highly purified single cells. Both P-glycoprotein and MRP-mediated efflux are present in human CD34+CD38- hematopoietic stem cells. Cytometry 49:135,142, 2002. © 2002 Wiley-Liss, Inc. [source] Delayed embryonic development and impaired cell growth and survival in Actg1 null mice,CYTOSKELETON, Issue 9 2010Tina M. Bunnell Abstract Actins are among the most highly expressed proteins in eukaryotes and play a central role in nearly all aspects of cell biology. While the intricate process of development undoubtedly requires a properly regulated actin cytoskeleton, little is known about the contributions of different actin isoforms during embryogenesis. Of the six actin isoforms, only the two cytoplasmic actins, ,cyto - and ,cyto -actin, are ubiquitously expressed. We found that ,cyto -actin null (Actg1,/,) mice were fully viable during embryonic development, but most died within 48 h of birth due to respiratory failure and cannibalization by the parents. While no morphogenetic defects were identified, Actg1,/, mice exhibited stunted growth during embryonic and postnatal development as well as delayed cardiac outflow tract formation that resolved by birth. Using primary mouse embryonic fibroblasts, we confirm that ,cyto -actin is not required for cell migration. The Actg1,/, cells, however, exhibited growth impairment and reduced cell viability, defects which perhaps contribute to the stunted growth and developmental delays observed in Actg1,/, embryos. Since the total amount of actin protein was maintained in Actg1,/, cells, our data suggests a distinct requirement for ,cyto -actin in cell growth and survival. © 2010 Wiley-Liss, Inc. [source] Fascin1 is dispensable for mouse development but is favorable for neonatal survivalCYTOSKELETON, Issue 8 2009Yoshihiko Yamakita Abstract Fascin1, an actin-bundling protein, has been demonstrated to be critical for filopodia formation in cultured cells, and thus is believed to be vital in motile activities including neurite extension and cell migration. To test whether fascin1 plays such essential roles within a whole animal, we have generated and characterized fascin1-deficient mice. Unexpectedly, fascin1-deficient mice are viable and fertile with no major developmental defect. Nissl staining of serial coronal brain sections reveals that fascin1-deficient brain is grossly normal except that knockout mouse brain lacks the posterior region of the anterior commissure neuron and has larger lateral ventricle. Fascin1-deficient, dorsal root ganglion neurons are able to extend neurites in vitro as well as those from wild-type mice, although fascin1-deficient growth cones are smaller and exhibit fewer and shorter filopodia than wild-type counterparts. Likewise, fascin1-deficient, embryonic fibroblasts are able to assemble filopodia, though filopodia are fewer, shorter and short-lived. These results indicate that fascin1-mediated filopodia assembly is dispensable for mouse development. Cell Motil. Cytoskeleton 2009. © 2009 Wiley-Liss, Inc. [source] Mutagenesis of ,-tubulin cysteine residues in Saccharomyces cerevisiae: Mutation of cysteine 354 results in cold-stable microtubulesCYTOSKELETON, Issue 2 2001Mohan L. Gupta Jr. Abstract Cysteine residues play important roles in the control of tubulin function. To determine which of the six cysteine residues in ,-tubulin are critical to tubulin function, we mutated the cysteines in Saccharomyces cerevisiae ,-tubulin individually to alanine and serine residues. Of the twelve mutations, only three produced significant effects: C12S, C354A, and C354S. The C12S mutation was lethal in the haploid, but the C12A mutation had no observable phenotype. Based on interactive views of the electron crystallographic structure of tubulin, we suggest that substitution of serine for cysteine at this position has a destabilizing effect on the interaction of tubulin with the exchangeable GTP. The two C354 mutations, although not lethal, produced dramatic effects on microtubules and cellular processes that require microtubules. The C354 mutant cells had decreased growth rates, a slowed mitosis, increased resistance to benomyl, and impaired nuclear migration and spindle assembly. The C354A mutation produced a more severe phenotype than the C354S mutation: the haploid cells had chromosome segregation defects, only 50% of cells in a culture were viable, and a significant percentage of the cells were misshapened. Cytoplasmic microtubules in the C354S and C354A cells were longer than in the control strain and spindle structures appeared shorter and thicker. Both cytoplasmic and spindle microtubules in the two C354 mutants were extremely stable to cold temperature. After 24 h at 4°C, the microtubules were still present and, in fact, very long and thick tubulin polymers had formed. Evidence exists to indicate that the C354 residue in mammalian tubulin is near the colchicine binding site and the electron crystal structure of tubulin places the residue at the interface between the ,- and ,-subunits. The sulfhydryl group is situated in a polar environment, which may explain why the alanine mutation is more severe than the serine mutation. When the C12S and the two C354 mutations were made in a diploid strain, the mutated tubulin was incorporated into microtubules and the resulting heterozygotes had phenotypes that were intermediate between those of the mutated haploids and the wild-type strains. The results suggest that the C12 and C354 residues play important roles in the structure and function of tubulin. Cell Motil. Cytoskeleton 49:67,77, 2001. © 2001 Wiley-Liss, Inc. [source] Assessment of post-traumatic PDL cells viability by a novel collagenase assayDENTAL TRAUMATOLOGY, Issue 4 2002Roberta Pileggi Abstract,,,Both length of extra-alveolar time and type of storage media are significant factors that can affect the long-term prognosis for replanted teeth. Numerous studies have examined various media in an attempt to determine the ideal material for storage of the avulsed tooth. The purpose of this study was to compare the number of viable periodontium ligament (PDL) cells in different storage media using a collagenase assay. Thirty-three freshly extracted human teeth were divided into four experimental and two control groups. The positive and negative controls corresponded to 0 min and an 8-h dry time, respectively. The experimental teeth were stored dry for 30 min and then immersed in one of four media (Hank's balanced salt solution (HBSS), milk, saline, water) for 45 min. The teeth were then treated with dispase grade II and collagenase for 30 min. The number of viable and nonviable PDL cells was counted with a hemocytometer and analyzed. An anova demonstrated no statistically significant differences in the viability of PDL cells among saline, HBSS and milk. Within the parameters of this study, it appears that milk or saline is an equally viable alternative to HBSS for storage of avulsed teeth. [source] System Complexity As a Measure of Safe Capacity for the Emergency DepartmentACADEMIC EMERGENCY MEDICINE, Issue 11 2006Daniel J. France PhD Objectives System complexity is introduced as a new measure of system state for the emergency department (ED). In its original form, the measure quantifies the uncertainty of demands on system resources. For application in the ED, the measure is being modified to quantify both workload and uncertainty to produce a single integrated measure of system state. Methods Complexity is quantified using an information-theoretic or entropic approach developed in manufacturing and operations research. In its original form, complexity is calculated on the basis of four system parameters: 1) the number of resources (clinicians and processing entities such as radiology and laboratory systems), 2) the number of possible work states for each resource, 3) the probability that a resource is in a particular work state, and 4) the probability of queue changes (i.e., where a queue is defined by the number of patients or patient orders being managed by a resource) during a specified time period. Results An example is presented to demonstrate how complexity is calculated and interpreted for a simple system composed of three resources (i.e., emergency physicians) managing varying patient loads. The example shows that variation in physician work states and patient queues produces different scores of complexity for each physician. It also illustrates how complexity and workload differ. Conclusions System complexity is a viable and technically feasible measurement for monitoring and managing surge capacity in the ED. [source] The Potential Role of Minoxidil in the Hair Transplantation SettingDERMATOLOGIC SURGERY, Issue 10 2002Marc R. Avram background. Over the last decade surgical management of hair loss has become an increasingly popular and satisfying procedure for both men and women, as innovations in donor harvesting, graft size, and hairline design have resulted in consistently natural-appearing hair restoration. objective. In addition, a better understanding of the regulation of the hair-growth cycle has led to advances in the pharmacologic treatment of androgenetic alopecia. methods. Currently there are two U.S. Food and Drug Administration (FDA)-approved agents that promote hair regrowth: over-the-counter topical minoxidil solution for men and women and prescription oral finasteride tablets for men. In October 2001, a group of 11 international experts on hair loss and hair transplantation convened to review the physiology and effects of pharmacologic treatments of hair loss and to discuss the value of administering topical minoxidil therapy as an adjunct to hair transplantation. results. This article presents the key findings and consensus points among the participants, including their current use of pharmacologic treatments, strategies for optimal results both pre- and postsurgery, and the importance of realistic patient expectations and compliance. conclusions. Based on the surgeons' clinical experience, the use of approved hair regrowth agents in hair transplant patients with viable but suboptimally functioning follicles in the region to be transplanted can increase hair density, speed regrowth in transplanted follicles, and complement the surgical result by slowing down or stopping further hair loss. [source] Generation and characterization of a novel neural crest marker allele, Inka1-LacZ, reveals a role for Inka1 in mouse neural tube closureDEVELOPMENTAL DYNAMICS, Issue 4 2010Bethany S. Reid Abstract Previous studies identified Inka1 as a gene regulated by AP-2, in the neural crest required for craniofacial morphogenesis in fish and frog. Here, we extend the analysis of Inka1 function and regulation to the mouse by generating a LacZ knock-in allele. Inka1-LacZ allele expression occurs in the cephalic mesenchyme, heart, and paraxial mesoderm prior to E8.5. Subsequently, expression is observed in the migratory neural crest cells and their derivatives. Consistent with expression of Inka1 in tissues of the developing head during neurulation, a low percentage of Inka1,/, mice show exencephaly while the remainder are viable and fertile. Further studies indicate that AP-2, is not required for Inka1 expression in the mouse, and suggest that there is no significant genetic interaction between these two factors during embryogenesis. Together, these data demonstrate that while the expression domain of Inka1 is conserved among vertebrates, its function and regulation are not. Developmental Dynamics 239:1188,1196, 2010. © 2010 Wiley-Liss, Inc. [source] Analysis of conserved residues in the ,pat-3 cytoplasmic tail reveals important functions of integrin in multiple tissuesDEVELOPMENTAL DYNAMICS, Issue 3 2010Xiaojian Xu Abstract Integrin cytoplasmic tails contain motifs that link extracellular information to cell behavior such as cell migration and contraction. To investigate the cell functions mediated by the conserved motifs, we created mutations in the Caenorhabditis elegans ,pat-3 cytoplasmic tail. The ,1D (799FK800), NPXY, tryptophan (784W), and threonine (797TT798) motifs were disrupted to identify their functions in vivo. Animals expressing integrins with disrupted NPXY motifs were viable, but displayed distal tip cell migration and ovulation defects. The conserved threonines were required for gonad migration and contraction as well as tail morphogenesis, whereas disruption of the ,1D and tryptophan motifs produced only mild defects. To abolish multiple conserved motifs, a ,1C-like variant, which results in a frameshift, was constructed. The ,pat-3(,1C) transgenic animals showed cold-sensitive larval arrests and defective muscle structure and gonad migration and contraction. Our study suggests that the conserved NPXY and TT motifs play important roles in the tissue-specific function of integrin. Developmental Dynamics 239:763,772, 2010. © 2010 Wiley-Liss, Inc. [source] Zinc-finger paralogues tsh and tio are functionally equivalent during imaginal development in Drosophila and maintain their expression levels through auto- and cross-negative feedback loopsDEVELOPMENTAL DYNAMICS, Issue 1 2009José Bessa Abstract teashirt (tsh) and tiptop (tio) are two Drosophila gene paralogues encoding zinc-finger transcription factors. While tsh is an important developmental regulator, tio null individuals are viable and fertile. Here, we show that tio and tsh have coincident expression domains in the imaginal discs, the precursors of the adult body, and that both genes show similar functional properties when expressed ectopically. Furthermore, tio is able to rescue the development of tsh mutants, indicating that both genes are functionally equivalent during imaginal development. Of interest, the transcriptional regulation of tio and tsh is linked by a negative feedback loop. This mechanism might be required to maintain a tight control on the total levels of tio/tsh and could help explaining why Drosophila keeps an apparently dispensable gene. Developmental Dynamics 238:19,28, 2009. © 2008 Wiley-Liss, Inc. [source] Sp1/Sp3 compound heterozygous mice are not viable: Impaired erythropoiesis and severe placental defectsDEVELOPMENTAL DYNAMICS, Issue 10 2007Imme Krüger No abstract is available for this article. [source] Shb null allele is inherited with a transmission ratio distortion and causes reduced viability in uteroDEVELOPMENTAL DYNAMICS, Issue 9 2007Vitezslav Kriz Abstract SHB is an Src homology 2 domain-containing adapter protein that has been found to be involved in numerous cellular responses. We have generated an Shb knockout mouse. No Shb,/, pups or embryos were obtained on the C57Bl6 background, indicating an early defect as a consequence of Shb - gene inactivation on this genetic background. Breeding heterozygotes for Shb gene inactivation (Shb+/,) on a mixed genetic background (FVB/C57Bl6/129Sv) reveals a distorted transmission ratio of the null allele with reduced numbers of Shb+/+ and Shb,/, animals, but increased number of Shb+/, animals. The Shb, allele is associated with various forms of malformations, explaining the relative reduction in the number of Shb,/, offspring. Shb,/, animals that were born were viable, fertile, and showed no obvious defects. However, Shb+/, female mice ovulated preferentially Shb, oocytes explaining the reduced frequency of Shb+/+ mice. Our study suggests a role of SHB during reproduction and development. Developmental Dynamics 236:2485,2492, 2007. © 2007 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||