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Sample records for cells escalates aggregation

  1. Cell aggregation and sedimentation.

    Science.gov (United States)

    Davis, R H

    1995-01-01

    The aggregation of cells into clumps or flocs has been exploited for decades in such applications as biological wastewater treatment, beer brewing, antibiotic fermentation, and enhanced sedimentation to aid in cell recovery or retention. More recent research has included the use of cell aggregation and sedimentation to selectively separate subpopulations of cells. Potential biotechnological applications include overcoming contamination, maintaining plasmid-bearing cells in continuous fermentors, and selectively removing nonviable hybridoma cells from perfusion cultures.

  2. Dose escalation for unresectable locally advanced non-small cell lung cancer: end of the line?

    Science.gov (United States)

    Hong, Julian C; Salama, Joseph K

    2016-02-01

    Radiation Therapy Oncology Group (RTOG) 0617 was a randomized trial that investigated both the impact of radiation dose-escalation and the addition of cetuximab on the treatment of non-small cell lung cancer (NSCLC). The results of RTOG 0617 were surprising, with the dose escalation randomization being closed prematurely due to futility stopping rules, and cetuximab ultimately showing no overall survival benefit. Locally advanced unresectable NSCLC has conventionally been treated with concurrent chemoradiation. Though advances in treatment technology have improved the ability to deliver adequate treatment dose, the foundation for radiotherapy (RT) has remained the same since the 1980s. Since then, progressive studies have sought to establish the safety and efficacy of escalating radiation dose to loco-regional disease. Though RTOG 0617 did not produce the anticipated result, much interest remains in dose escalation and establishing an explanation for the findings of this study. Cetuximab was also not found to provide a survival benefit when applied to an unselected population. However, planned retrospective analysis suggests that those patients with high epidermal growth factor receptor (EGFR) expression may benefit, suggesting that cetuximab should be applied in a targeted fashion. We discuss the results of RTOG 0617 and additional findings from post-hoc analysis that suggest that dose escalation may be limited by normal tissue toxicity. We also present ongoing studies that aim to address potential causes for mortality in the dose escalation arm through adaptive or proton therapy, and are also leveraging additional concurrent systemic agents such as tyrosine kinase inhibitors (TKIs) for EGFR-activating mutations or EML4-ALK rearrangements, and poly (ADP-ribose) polymerase (PARP) inhibitors.

  3. Strategy Escalation: An emerging paradigm for safe clinical development of T cell gene therapies

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    Junghans Richard

    2010-06-01

    Full Text Available Abstract Gene therapy techniques are being applied to modify T cells with chimeric antigen receptors (CARs for therapeutic ends. The versatility of this platform has spawned multiple options for their application with new permutations in strategies continually being invented, a testimony to the creative energies of many investigators. The field is rapidly expanding with immense potential for impact against diverse cancers. But this rapid expansion, like the Big Bang, comes with a somewhat chaotic evolution of its therapeutic universe that can also be dangerous, as seen by recently publicized deaths. Time-honored methods for new drug testing embodied in Dose Escalation that were suitable for traditional inert agents are now inadequate for these novel "living drugs". In the following, I propose an approach to escalating risk for patient exposures with these new immuno-gene therapy agents, termed Strategy Escalation, that accounts for the molecular and biological features of the modified cells and the methods of their administration. This proposal is offered not as a prescriptive but as a discussion framework that investigators may wish to consider in configuring their intended clinical applications.

  4. Distinguishing aggregate formation and aggregate clearance using cell based assays

    NARCIS (Netherlands)

    E. Eenjes, E.; J.M. Dragich; H. Kampinga (Harm); A. Yamamoto, A.

    2016-01-01

    textabstractThe accumulation of ubiquitinated proteinaceous inclusions represents a complex process, reflecting the disequilibrium between aggregate formation and aggregate clearance. Although decreasing aggregate formation or augmenting aggregate clearance will ultimately lead to diminished aggrega

  5. Rituximab and escalated chemotherapy in elderly patients with aggressive diffuse large-cell lymphoma: a controlled clinical trial.

    Science.gov (United States)

    Avilés, Agustin; Nambo, María Jesus; Castañeda, Claudia; Cleto, Sergio; Neri, Natividad; Murillo, Edgar; Huerta-Guzmán, Judith; Contreras, Margarita

    2007-04-01

    The treatment of elderly patients with aggressive malignant lymphoma has not been defined. The addition of rituximab to conventional chemotherapy has been reported to improve the outcome, but most patients have good prognostic factors (performance status < 2, no severe associated diseases, low or low-intermediate clinical risk). Thus, we developed a combined regimen, including escalated doses of anthracycline and rituximab. The endpoint was to improve event-free survival (EFS) and overall survival. Two hundred and four (204) patients were randomly assigned to receive an escalated chemotherapy regimen (CEOP) with escalated dose of epirubicin, compared to the same regimen and addition of rituximab. All patients had poor prognostic factors: high- or high-intermediate clinical risk, poor performance status, bulky disease, and more than 2 with extranodal involvement. In an intent-to-treat analysis, all patients were evaluable for efficacy and toxicity. The complete response rates were similar in both arms: 74% in chemotherapy and 78% in the rituximab + chemotherapy program. EFS and overall survival were similar: 77% and 84%, respectively, in combined chemotherapy and 75% and 81% in the rituximab-chemotherapy regimen. Toxicity was mild and well tolerated. In elderly patients with diffuse large-cell lymphoma and poor prognostic factors, rituximab did not improve their outcome.

  6. Strategies of dose escalation in the treatment of locally advanced non-small cell lung cancer: image guidance and beyond

    Directory of Open Access Journals (Sweden)

    Alexander eChi

    2014-06-01

    Full Text Available Radiation dose in the setting of chemo-radiation for locally advanced non-small cell lung cancer (NSCLC has been historically limited by the risk of normal tissue toxicity and this has been hypothesized to correlate with the poor results in regard to local tumor recurrences. Dose escalation, as a means to improve local control, with concurrent chemotherapy has been shown to be feasible with three-dimensional conformal radiotherapy in early phase studies with good clinical outcome. However, the potential superiority of moderate dose escalation to 74 Gy has not been shown in phase III randomized studies. In this review, the limitations in target volume definition in previous studies; and the factors that may be critical to safe dose escalation in the treatment of locally advanced NSCLC, such as respiratory motion management, image guidance, intensity modulation, FDG-PET incorporation in the treatment planning process, and adaptive radiotherapy, are discussed. These factors, along with novel treatment approaches that have emerged in recent years, are proposed to warrant further investigation in future trials in a more comprehensive and integrated fashion.

  7. Thrombolytic therapy reduces red blood cell aggregation in plasma without affecting intrinsic aggregability.

    Science.gov (United States)

    Ben-Ami, R; Sheinman, G; Yedgar, S; Eldor, A; Roth, A; Berliner, A S; Barshtein, G

    2002-03-15

    Red blood cell (RBC) aggregation may contribute to occlusion of the coronary microcirculation during myocardial infarction. We studied the effect of thrombolytic therapy on RBC aggregation in patients with acute myocardial infarction (AMI). Compared with patients with myocardial infarction who did not receive thrombolytic therapy, those treated with systemic thrombolysis exhibited significantly reduced RBC aggregation, reduced plasma fibrinogen levels and increased plasma D-dimer levels. Using measurement of RBC aggregation in a standardized dextran-500 solution, reduction in RBC aggregation after thrombolysis was shown to be plasma dependent. Thrombolytic therapy had no direct effect on intrinsic RBC aggregability in patients with AMI. We conclude that thrombolytic therapy has rheologic consequences that may contribute to its overall efficacy. Inhibition of RBC aggregation by thrombolytic therapy may result from the degradation of fibrinogen, a key factor in the formation of RBC aggregates, and from the generation of fibrinogen degradation products capable of disaggregating RBCs.

  8. p53 Aggregates penetrate cells and induce the co-aggregation of intracellular p53.

    Directory of Open Access Journals (Sweden)

    Karolyn J Forget

    Full Text Available Prion diseases are unique pathologies in which the infectious particles are prions, a protein aggregate. The prion protein has many particular features, such as spontaneous aggregation, conformation transmission to other native PrP proteins and transmission from an individual to another. Protein aggregation is now frequently associated to many human diseases, for example Alzheimer's disease, Parkinson's disease or type 2 diabetes. A few proteins associated to these conformational diseases are part of a new category of proteins, called prionoids: proteins that share some, but not all, of the characteristics associated with prions. The p53 protein, a transcription factor that plays a major role in cancer, has recently been suggested to be a possible prionoid. The protein has been shown to accumulate in multiple cancer cell types, and its aggregation has also been reproduced in vitro by many independent groups. These observations suggest a role for p53 aggregates in cancer development. This study aims to test the «prion-like» features of p53. Our results show in vitro aggregation of the full length and N-terminally truncated protein (p53C, and penetration of these aggregates into cells. According to our findings, the aggregates enter cells using macropinocytosis, a non-specific pathway of entry. Lastly, we also show that once internalized by the cell, p53C aggregates can co-aggregate with endogenous p53 protein. Together, these findings suggest prion-like characteristics for p53 protein, based on the fact that p53 can spontaneously aggregate, these aggregates can penetrate cells and co-aggregate with cellular p53.

  9. Optimizing Collimator Margins for Isotoxically Dose-Escalated Conformal Radiation Therapy of Non-Small Cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Samantha, E-mail: Samantha.warren@oncology.ox.ac.uk [Department of Oncology, Gray Institute of Radiation Oncology and Biology, University of Oxford, Oxford (United Kingdom); Oxford Cancer Centre, Oxford University Hospitals, Oxford (United Kingdom); Panettieri, Vanessa [William Buckland Radiotherapy Centre, Alfred Hospital, Commercial Road, Melbourne (Australia); Panakis, Niki; Bates, Nicholas [Oxford Cancer Centre, Oxford University Hospitals, Oxford (United Kingdom); Lester, Jason F. [Velindre Cancer Centre, Velindre Road, Whitchurch, Cardiff (United Kingdom); Jain, Pooja [Clatterbridge Cancer Centre, Clatterbridge Road, Wirral (United Kingdom); Landau, David B. [Department of Radiotherapy, Guy' s and St. Thomas' NHS Foundation Trust, London (United Kingdom); Nahum, Alan E.; Mayles, W. Philip M. [Clatterbridge Cancer Centre, Clatterbridge Road, Wirral (United Kingdom); Fenwick, John D. [Department of Oncology, Gray Institute of Radiation Oncology and Biology, University of Oxford, Oxford (United Kingdom); Oxford Cancer Centre, Oxford University Hospitals, Oxford (United Kingdom)

    2014-04-01

    Purpose: Isotoxic dose escalation schedules such as IDEAL-CRT [isotoxic dose escalation and acceleration in lung cancer chemoradiation therapy] (ISRCTN12155469) individualize doses prescribed to lung tumors, generating a fixed modeled risk of radiation pneumonitis. Because the beam penumbra is broadened in lung, the choice of collimator margin is an important element of the optimization of isotoxic conformal radiation therapy for lung cancer. Methods and Materials: Twelve patients with stage I-III non-small cell lung cancer (NSCLC) were replanned retrospectively using a range of collimator margins. For each plan, the prescribed dose was calculated according to the IDEAL-CRT isotoxic prescription method, and the absolute dose (D{sub 99}) delivered to 99% of the planning target volume (PTV) was determined. Results: Reducing the multileaf collimator margin from the widely used 7 mm to a value of 2 mm produced gains of 2.1 to 15.6 Gy in absolute PTV D{sub 99}, with a mean gain ± 1 standard error of the mean of 6.2 ± 1.1 Gy (2-sided P<.001). Conclusions: For NSCLC patients treated with conformal radiation therapy and an isotoxic dose prescription, absolute doses in the PTV may be increased by using smaller collimator margins, reductions in relative coverage being offset by increases in prescribed dose.

  10. Mathematical modelling of cell aggregation in liver tissue engineering

    OpenAIRE

    Green, John Edward E.

    2006-01-01

    A promising method for growing functional liver tissue in vitro involves culturing hepatocytes as spheroidal cell aggregates. In this thesis, we develop mathematical models of cell aggregation, and use them to determine how hepatocytes' interactions with the extracellular matrix (ECM) on which they are seeded, and with stellate cells, affect the process. Chapters 2-4 focus on the effect that cell-ECM coupling has on the aggregation process. We use a novel formulation that couples a mechani...

  11. Tracking Hypoxic Signaling within Encapsulated Cell Aggregates

    Science.gov (United States)

    Skiles, Matthew L.; Sahai, Suchit; Blanchette, James O.

    2011-01-01

    nutrients, notably oxygen, is therefore reduced and limited by diffusion. This reduced oxygen availability may especially impact β-cells whose insulin secretory function is highly dependent on oxygen11-13. Capsule composition and geometry will also impact diffusion rates and lengths for oxygen. Therefore, we also describe a technique for identifying hypoxic cells within our PEG capsules. Infection of the cells with a recombinant adenovirus allows for a fluorescent signal to be produced when intracellular hypoxia-inducible factor (HIF) pathways are activated14. As HIFs are the primary regulators of the transcriptional response to hypoxia, they represent an ideal target marker for detection of hypoxic signaling15. This approach allows for easy and rapid detection of hypoxic cells. Briefly, the adenovirus has the sequence for a red fluorescent protein (Ds Red DR from Clontech) under the control of a hypoxia-responsive element (HRE) trimer. Stabilization of HIF-1 by low oxygen conditions will drive transcription of the fluorescent protein (Figure 1). Additional details on the construction of this virus have been published previously15. The virus is stored in 10% glycerol at -80° C as many 150 μL aliquots in 1.5 mL centrifuge tubes at a concentration of 3.4 x 1010 pfu/mL. Previous studies in our lab have shown that MIN6 cells encapsulated as aggregates maintain their viability throughout 4 weeks of culture in 20% oxygen. MIN6 aggregates cultured at 2 or 1% oxygen showed both signs of necrotic cells (still about 85-90% viable) by staining with ethidium bromide as well as morphological changes relative to cells in 20% oxygen. The smooth spherical shape of the aggregates displayed at 20% was lost and aggregates appeared more like disorganized groups of cells. While the low oxygen stress does not cause a pronounced drop in viability, it is clearly impacting MIN6 aggregation and function as measured by glucose-stimulated insulin secretion15. Western blot analysis of encapsulated

  12. Tracking hypoxic signaling within encapsulated cell aggregates.

    Science.gov (United States)

    Skiles, Matthew L; Sahai, Suchit; Blanchette, James O

    2011-12-16

    , is therefore reduced and limited by diffusion. This reduced oxygen availability may especially impact β-cells whose insulin secretory function is highly dependent on oxygen. Capsule composition and geometry will also impact diffusion rates and lengths for oxygen. Therefore, we also describe a technique for identifying hypoxic cells within our PEG capsules. Infection of the cells with a recombinant adenovirus allows for a fluorescent signal to be produced when intracellular hypoxia-inducible factor (HIF) pathways are activated. As HIFs are the primary regulators of the transcriptional response to hypoxia, they represent an ideal target marker for detection of hypoxic signaling. This approach allows for easy and rapid detection of hypoxic cells. Briefly, the adenovirus has the sequence for a red fluorescent protein (Ds Red DR from Clontech) under the control of a hypoxia-responsive element (HRE) trimer. Stabilization of HIF-1 by low oxygen conditions will drive transcription of the fluorescent protein (Figure 1). Additional details on the construction of this virus have been published previously. The virus is stored in 10% glycerol at -80° C as many 150 μL aliquots in 1.5 mL centrifuge tubes at a concentration of 3.4 x 10(10) pfu/mL. Previous studies in our lab have shown that MIN6 cells encapsulated as aggregates maintain their viability throughout 4 weeks of culture in 20% oxygen. MIN6 aggregates cultured at 2 or 1% oxygen showed both signs of necrotic cells (still about 85-90% viable) by staining with ethidium bromide as well as morphological changes relative to cells in 20% oxygen. The smooth spherical shape of the aggregates displayed at 20% was lost and aggregates appeared more like disorganized groups of cells. While the low oxygen stress does not cause a pronounced drop in viability, it is clearly impacting MIN6 aggregation and function as measured by glucose-stimulated insulin secretion. Western blot analysis of encapsulated cells in 20% and 1% oxygen also

  13. A planning study of radiotherapy dose escalation of PET-active tumour volumes in non-small cell lung cancer patients

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    Sloth Moeller, Ditte; Hoffmann, Lone (Dept. of Medical Physics, Aarhus Univ. Hospital, Aarhus (Denmark)), e-mail: dittmoel@rm.dk; Khalil, Azza Ahmed; Marquard Knap, Marianne (Dept. of Oncology, Aarhus Univ. Hospital, Aarhus (Denmark)); Muren, Ludvig Paul (Dept. of Medical Physics, Aarhus Univ. Hospital, Aarhus (Denmark); Dept. of Oncology, Aarhus Univ. Hospital, Aarhus (Denmark))

    2011-08-15

    Background. Patients with non-small cell lung cancer (NSCLC) have poor prognosis partly because of high local failure rates. Escalating the dose to the tumour may decrease the local failure rates and thereby, improve overall survival, but the risk of complications will limit the possibility to dose-escalate a broad range of patients. Escalating only PET-active areas of the tumour may increase the potential for reaching high doses for a variety of tumour sizes and locations. Material and methods. Ten patients were randomly chosen for a dose escalation planning study. A planning target volume (PTV) was defined on the mid-ventilation scan of a four-dimensional computed tomography (4D-CT) scan and a boost planning target volume (PTV-boost) was defined based on a positron emission tomography computed tomography (PET-CT) scan. Treatment plans were created aiming to reach the highest achievable of 74 Gy, 78 Gy or 82 Gy in 2 Gy per fraction prescribed to the PTV-boost without compromising normal tissue constraints and with the PTV prescribed in all cases a biological equivalent dose in 2 Gy fractions of 66 Gy. Results. Nine of ten patients could be escalated to the highest dose level (82 Gy), while one patient was limited by the oesophagus dose constraint and could only reach 74 Gy. Four patients could be dose-escalated above 82 Gy without compromising normal tissue constraints. Conclusion. Dose-escalating only the PET-active areas of lung tumours to doses of 82 Gy while respecting normal tissue constraints is feasible, also in a series of unselected patients including cases with relatively large tumours

  14. Dose escalation of the hypoxic cell sensitizer etanidazole combined with ifosfamide, carboplatin, etoposide, and autologous hematopoietic stem cell support.

    Science.gov (United States)

    Elias, A D; Wheeler, C; Ayash, L J; Schwartz, G; Ibrahim, J; Mills, L; McCauley, M; Coleman, N; Warren, D; Schnipper, L; Antman, K H; Teicher, B A; Frei, E

    1998-06-01

    Multiple mechanisms of drug resistance contribute to treatment failure. Although high-dose therapy attempts to overwhelm these defenses pharmacologically, this approach is only successful in a fraction of treated patients. Many drug resistance mechanisms are shared between malignant and normal cells, but the expression of various drug resistance mechanisms associated with hypoxia is largely confined to tumor tissue. Thus, reversal of this mechanism is likely to provide a therapeutic advantage to the host. This study was designed to define the dose-limiting toxicities and maximum tolerated dose of etanidazole when it is given concurrently with high-dose ifosfamide, carboplatin, and etoposide (ICE), with hematopoietic stem cell support. The maximum tolerated doses of high-dose ICE were administered concurrently with dose escalations of etanidazole, a hypoxic cell sensitizer. All agents were given by 96-h continuous i.v. infusion beginning on day -7. Mesna uroprotection was provided. Autologous marrow and cytokine mobilized peripheral blood progenitor cells were reinfused on day 0. Granulocyte colony-stimulating factor was administered following reinfusion until the granulocytes recovered to > 1000/microliter. Fifty-five adults with advanced malignancies were enrolled in cohorts of five to nine patients. Four dose levels of etanidazole between 3 and 5.5 g/m2/day (12, 16, 20, and 22 g/m2 total doses) and two doses of carboplatin (1600 and 1800 mg/m2 total doses) were evaluated. Seven patients died of organ toxicity (13%); two each from veno-occlusive disease of liver and sepsis; and one each from sudden death, renal failure, and refractory thrombocytopenic hemorrhage. Five deaths occurred at the top dose level. One additional patient suffered a witnessed cardiorespiratory arrest from ventricular fibrillation and was resuscitated. Dose-dependent and largely reversible peripheral neuropathy was observed consisting of two syndromes: severe cramping myalgic/neuralgic pain

  15. Dose Escalation of Total Marrow Irradiation With Concurrent Chemotherapy in Patients With Advanced Acute Leukemia Undergoing Allogeneic Hematopoietic Cell Transplantation

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    Wong, Jeffrey Y.C., E-mail: jwong@coh.org [Department of Radiation Oncology, City of Hope National Medical Center, Duarte, California (United States); Forman, Stephen; Somlo, George [Department of Hematology/Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, California (United States); Rosenthal, Joseph [Department of Hematology/Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, California (United States); Department of Pediatrics, City of Hope National Medical Center, Duarte, California (United States); Liu An; Schultheiss, Timothy; Radany, Eric [Department of Radiation Oncology, City of Hope National Medical Center, Duarte, California (United States); Palmer, Joycelynne [Department of Biostatistics, City of Hope National Medical Center, Duarte, California (United States); Stein, Anthony [Department of Hematology/Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, California (United States)

    2013-01-01

    Purpose: We have demonstrated that toxicities are acceptable with total marrow irradiation (TMI) at 16 Gy without chemotherapy or TMI at 12 Gy and the reduced intensity regimen of fludarabine/melphalan in patients undergoing hematopoietic cell transplantation (HCT). This article reports results of a study of TMI combined with higher intensity chemotherapy regimens in 2 phase I trials in patients with advanced acute myelogenous leukemia or acute lymphoblastic leukemia (AML/ALL) who would do poorly on standard intent-to-cure HCT regimens. Methods and Materials: Trial 1 consisted of TMI on Days -10 to -6, etoposide (VP16) on Day -5 (60 mg/kg), and cyclophosphamide (CY) on Day -3 (100 mg/kg). TMI dose was 12 (n=3 patients), 13.5 (n=3 patients), and 15 (n=6 patients) Gy at 1.5 Gy twice daily. Trial 2 consisted of busulfan (BU) on Days -12 to -8 (800 {mu}M min), TMI on Days -8 to -4, and VP16 on Day -3 (30 mg/kg). TMI dose was 12 (n=18) and 13.5 (n=2) Gy at 1.5 Gy twice daily. Results: Trial 1 had 12 patients with a median age of 33 years. Six patients had induction failures (IF), and 6 had first relapses (1RL), 9 with leukemia blast involvement of bone marrow ranging from 10%-98%, 5 with circulating blasts (24%-85%), and 2 with chloromas. No dose-limiting toxicities were observed. Eleven patients achieved complete remission at Day 30. With a median follow-up of 14.75 months, 5 patients remained in complete remission from 13.5-37.7 months. Trial 2 had 20 patients with a median age of 41 years. Thirteen patients had IF, and 5 had 1RL, 2 in second relapse, 19 with marrow blasts (3%-100%) and 13 with peripheral blasts (6%-63%). Grade 4 dose-limiting toxicities were seen at 13.5 Gy (stomatitis and hepatotoxicity). Stomatitis was the most frequent toxicity in both trials. Conclusions: TMI dose escalation to 15 Gy is possible when combined with CY/VP16 and is associated with acceptable toxicities and encouraging outcomes. TMI dose escalation is not possible with BU/VP16 due to

  16. Phase 1 Study of Dose Escalation in Hypofractionated Proton Beam Therapy for Non-Small Cell Lung Cancer

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    Gomez, Daniel R., E-mail: dgomez@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Gillin, Michael [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liao, Zhongxing [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Wei, Caimiao [Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Lin, Steven H.; Swanick, Cameron; Alvarado, Tina; Komaki, Ritsuko; Cox, James D.; Chang, Joe Y. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2013-07-15

    Background: Many patients with locally advanced non-small cell lung cancer (NSCLC) cannot undergo concurrent chemotherapy because of comorbidities or poor performance status. Hypofractionated radiation regimens, if tolerable, may provide an option to these patients for effective local control. Methods and Materials: Twenty-five patients were enrolled in a phase 1 dose-escalation trial of proton beam therapy (PBT) from September 2010 through July 2012. Eligible patients had histologically documented lung cancer, thymic tumors, carcinoid tumors, or metastatic thyroid tumors. Concurrent chemotherapy was not allowed, but concurrent treatment with biologic agents was. The dose-escalation schema comprised 15 fractions of 3 Gy(relative biological effectiveness [RBE])/fraction, 3.5 Gy(RBE)/fraction, or 4 Gy(RBE)/fraction. Dose constraints were derived from biologically equivalent doses of standard fractionated treatment. Results: The median follow-up time for patients alive at the time of analysis was 13 months (range, 8-28 months). Fifteen patients received treatment to hilar or mediastinal lymph nodes. Two patients experienced dose-limiting toxicity possibly related to treatment; 1 received 3.5-Gy(RBE) fractions and experienced an in-field tracheoesophageal fistula 9 months after PBT and 1 month after bevacizumab. The other patient received 4-Gy(RBE) fractions and was hospitalized for bacterial pneumonia/radiation pneumonitis 4 months after PBT. Conclusion: Hypofractionated PBT to the thorax delivered over 3 weeks was well tolerated even with significant doses to the lungs and mediastinal structures. Phase 2/3 trials are needed to compare the efficacy of this technique with standard treatment for locally advanced NSCLC.

  17. Linear aggregation theory in cell biology

    Energy Technology Data Exchange (ETDEWEB)

    Hill, T.L.

    1987-01-01

    This is an account of the theory, probability, and thermodynamics of linear aggregation. The emphasis is on basic principles illustrated by simple models, not on particular applications or polymers. The general physical aggregate systems - attached single-stranded polymers, single-stranded polymers modified by a second component, long multistranded polymers, attached multistranded polymers - are given extensive treatment. Also included are a discussion of the GTPase and ATPase activity accompanying the aggregation of microtubules and action, and the properties of the kinetic two-phase model of the end of a microtubule.

  18. Dose-Escalation Trial of Carfilzomib With and Without Romidepsin in Cutaneous T-Cell Lymphoma

    Science.gov (United States)

    2015-11-10

    Recurrent Cutaneous T-cell Non-Hodgkin Lymphoma; Recurrent Mycosis Fungoides/Sezary Syndrome; Stage I Cutaneous T-cell Non-Hodgkin Lymphoma; Stage IA Mycosis Fungoides/Sezary Syndrome; Stage IB Mycosis Fungoides/Sezary Syndrome; Stage II Cutaneous T-cell Non-Hodgkin Lymphoma; Stage IIA Mycosis Fungoides/Sezary Syndrome; Stage IIB Mycosis Fungoides/Sezary Syndrome; Stage III Cutaneous T-cell Non-Hodgkin Lymphoma; Stage IIIA Mycosis Fungoides/Sezary Syndrome; Stage IIIB Mycosis Fungoides/Sezary Syndrome; Stage IV Cutaneous T-cell Non-Hodgkin Lymphoma; Stage IVA Mycosis Fungoides/Sezary Syndrome; Stage IVB Mycosis Fungoides/Sezary Syndrome

  19. Aggregation of red blood cells in patients with Gaucher disease.

    Science.gov (United States)

    Adar, Tomer; Ben-Ami, Ronen; Elstein, Deborah; Zimran, Ari; Berliner, Shlomo; Yedgar, Saul; Barshtein, Gershon

    2006-08-01

    Gaucher disease is associated with increased red blood cell (RBC) aggregation, but the pathophysiological significance of this phenomenon and its correlation with disease manifestations are unclear. RBC aggregation was evaluated in 43 patients with Gaucher disease and 53 healthy controls. Dynamic RBC aggregation was examined in a narrow-gap flow chamber at varying shear stress. Compared with the controls, RBC aggregation in Gaucher disease was increased by 25%. Comparison of RBC aggregation in autologous plasma and in dextran (500 kDa) showed an increase both in plasma-dependent (extrinsic) and -independent (intrinsic) RBC aggregation. Subgroup analysis revealed that increased RBC aggregation was limited to patients with an intact spleen. RBC aggregation in patients did not correlate with plasma fibrinogen concentration, disease severity, enzyme replacement therapy or genotype. We conclude that RBC aggregation is increased in patients with Gaucher disease and an intact spleen, possibly reflecting the accumulation of glucocerebroside and other substances in the plasma and RBC membranes of these patients. Our results do not support a role for RBC aggregation in the pathogenesis of vascular complications of Gaucher disease.

  20. Simulation of red blood cell aggregation in shear flow.

    Science.gov (United States)

    Lim, B; Bascom, P A; Cobbold, R S

    1997-01-01

    A simulation model has been developed for red blood cell (RBC) aggregation in shear flow. It is based on a description of the collision rates of RBC, the probability of particles sticking together, and the breakage of aggregates by shear forces. The influence of shear rate, hematocrit, aggregate fractal dimension, and binding strength on aggregation kinetics were investigated and compared to other theoretical and experimental results. The model was used to simulate blood flow in a long large diameter tube under steady flow conditions at low Reynolds numbers. The time and spatial distribution of the state of aggregation are shown to be in qualitative agreement with previous B-mode ultrasound studies in which a central region of low echogenicity was noted. It is suggested that the model can provide a basis for interpreting prior measurements of ultrasound echogenicity and may help relate them to the local state of aggregation.

  1. Ralstonia insidiosa induces cell aggregation by Listeria monocytogenes

    Science.gov (United States)

    Biofilm formation is an important strategy for foodborne bacterial pathogens to survive in stressful environments such as fresh produce processing facilities. Bacterial cell aggregation strongly promotes the initiation of microcolonies and the formation of biofilms on abiological surfaces. We previ...

  2. Dosimetric Feasibility of Dose Escalation Using SBRT Boost for Stage III Non-Small Cell Lung Cancer

    Science.gov (United States)

    Hepel, Jaroslaw T.; Peter, Justin; Hiatt, Jessica R.; Patel, Salil; Osibanjo, Oluwademilade; Safran, Howard; Curran, Bruce; DiPetrillo, Thomas

    2012-01-01

    Purpose: Standard chemoradiation therapy for stage III non-small cell lung cancer (NSCLCa) results in suboptimal outcomes with a high rate of local failure and poor overall survival. We hypothesize that dose escalation using stereotactic body radiotherapy (SBRT) boost could improve upon these results. We present here a study evaluating the dosimetric feasibility of such an approach. Methods: Anonymized CT data sets from five randomly selected patients with stage III NSCLCa undergoing definitive chemoradiation therapy in our department with disease volumes appropriate for SBRT boost were selected. Three-dimensional conformal radiation therapy (3D-CRT) plans to 50.4 Gy in 28 fractions were generated follow by SBRT plans to two dose levels, 16 Gy in two fractions and 28 Gy in two fractions. SBRT plans and total composite (3D-CRT and SBRT) were optimized and evaluated for target coverage and dose to critical structures; lung, esophagus, cord, and heart. Results: All five plans met predetermined target coverage and normal tissue dose constraints. PTV V95 was equal to or greater than 95% in all cases. The cumulative lung V20 and V5 of the combined 3D-CRT and SBRT plans were less than or equal to 30 and 55%, respectively. The 5 cc esophageal dose was less than 12 Gy for all low and high dose SBRT plans. The cumulative dose to the esophagus was also acceptable with less than 10% of the esophagus receiving doses in excess of 50 Gy. The cumulative spinal cord dose was less than 33 Gy and heart V25 was less than 5%. Conclusion: The combination of chemoradiation to 50.4 Gy followed by SBRT boost to gross disease at the primary tumor and involved regional lymph nodes is feasible with respect to normal tissue dose constraints in this dosimetric pilot study. A phase I/II trial to evaluate the clinical safety and efficacy of this approach is being undertaken. PMID:23057009

  3. Chronotropic Biosensing Via Stem-Cell Derived Myocyte Aggregates

    Science.gov (United States)

    2007-11-02

    the example of Figure 2, the myocyte aggregates showed a high degree of ab - solute tracking; for the 6 sustained-activity aggregates, the cor- relation...chronotropy. Indeed, excitable-cell biosensor systems could lead to the development of long-term, physiologically- tuned, functionally integrated bioprocessing ...H. Ko- dama, J. Pan, M. Sano, T. Takahashi, S. Hori, H. Abe , J. Hata, A. Umezawa, and S. Ogawa, “Cardiomyocytes can be generated from marrow stromal

  4. Structural analysis of red blood cell aggregates under shear flow.

    Science.gov (United States)

    Chesnutt, J K W; Marshall, J S

    2010-03-01

    A set of measures of red blood cell (RBC) aggregates are developed and applied to examine the aggregate structure under plane shear and channel flows. Some of these measures are based on averages over the set of red blood cells which are in contact with each other at a given time. Other measures are developed by first fitting an ellipse to the planar projection of the aggregate, and then examining the area and aspect ratio of the fit ellipse as well as the orientations of constituent RBCs with respect to the fit ellipse axes. The aggregate structural measures are illustrated using a new mesoscale computational model for blood cell transport, collision and adhesion. The sensitivity of this model to change in adhesive surface energy density and shear rate on the aggregate structure is examined. It is found that the mesoscale model predictions exhibit reasonable agreement with experimental and theoretical data for blood flow in plane shear and channel flows. The new structural measures are used to examine the differences between predictions of two- and three-dimensional computations of the aggregate formation, showing that two-dimensional computations retain some of the important aspects of three-dimensional computations.

  5. Aggregation of Red Blood Cells: From Rouleaux to Clot Formation

    CERN Document Server

    Wagner, C; Svetina, S

    2013-01-01

    Red blood cells are known to form aggregates in the form of rouleaux. This aggregation process is believed to be reversible, but there is still no full understanding on the binding mechanism. There are at least two competing models, based either on bridging or on depletion. We review recent experimental results on the single cell level and theoretical analyses of the depletion model and of the influence of the cell shape on the binding strength. Another important aggregation mechanism is caused by activation of platelets. This leads to clot formation which is life saving in the case of wound healing but also a major cause of death in the case of a thrombus induced stroke. We review historical and recent results on the participation of red blood cells in clot formation.

  6. Before escalation: behavioral and affective forecasting in escalation of commitment.

    Science.gov (United States)

    Ku, Gillian

    2008-11-01

    This research examines preinvestment forecasting processes in escalation of commitment, considering two questions: whether individuals are able to accurately predict their behavior and affect in escalation situations and how forecasting processes may be linked to actual escalation. Three experiments demonstrated that individuals underpredicted their escalation and overpredicted their postescalation regret. Two of the experiments also indicated that the less individuals predicted being entrapped, the more they escalated. Counter to expectations, anticipated regret did not predict escalation. The discussion focuses on the theoretical and practical importance of forecasting on escalation and on the importance of understanding both behavioral and affective forecasting effects simultaneously.

  7. Precision Hypofractionated Radiation Therapy in Poor Performing Patients With Non-Small Cell Lung Cancer: Phase 1 Dose Escalation Trial

    Energy Technology Data Exchange (ETDEWEB)

    Westover, Kenneth D. [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Loo, Billy W. [Department of Radiation Oncology, Stanford University, Stanford, California (United States); Gerber, David E. [Division of Hematology-Oncology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Iyengar, Puneeth; Choy, Hak [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Diehn, Maximilian [Department of Radiation Oncology, Stanford University, Stanford, California (United States); Hughes, Randy; Schiller, Joan; Dowell, Jonathan [Division of Hematology-Oncology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Wardak, Zabi [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Sher, David [Department of Radiation Oncology, Rush University Medical Center, Chicago, Illinois (United States); Christie, Alana; Xie, Xian-Jin [Department of Clinical Science, Southwestern Medical Center, Dallas, Texas (United States); Corona, Irma [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Sharma, Akanksha [School of Medicine, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Wadsworth, Margaret E. [Radiation Oncology of Mississippi, Jackson, Mississippi (United States); Timmerman, Robert, E-mail: Robert.Timmerman@utsouthwestern.edu [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States)

    2015-09-01

    Purpose: Treatment regimens for locally advanced non-small cell lung cancer (NSCLC) give suboptimal clinical outcomes. Technological advancements such as radiation therapy, the backbone of most treatment regimens, may enable more potent and effective therapies. The objective of this study was to escalate radiation therapy to a tumoricidal hypofractionated dose without exceeding the maximally tolerated dose (MTD) in patients with locally advanced NSCLC. Methods and Materials: Patients with stage II to IV or recurrent NSCLC and Eastern Cooperative Oncology Group performance status of 2 or greater and not candidates for surgical resection, stereotactic radiation, or concurrent chemoradiation were eligible. Highly conformal radiation therapy was given to treat intrathoracic disease in 15 fractions to a total of 50, 55, or 60 Gy. Results: Fifty-five patients were enrolled: 15 at the 50-Gy, 21 at the 55-Gy, and 19 at the 60-Gy dose levels. A 90-day follow-up was completed in each group without exceeding the MTD. With a median follow-up of 12.5 months, there were 93 grade ≥3 adverse events (AEs), including 39 deaths, although most AEs were considered related to factors other than radiation therapy. One patient from the 55- and 60-Gy dose groups developed grade ≥3 esophagitis, and 5, 4, and 4 patients in the respective dose groups experienced grade ≥3 dyspnea, but only 2 of these AEs were considered likely related to therapy. There was no association between fraction size and toxicity (P=.24). The median overall survival was 6 months with no significant differences between dose levels (P=.59). Conclusions: Precision hypofractionated radiation therapy consisting of 60 Gy in 15 fractions for locally advanced NSCLC is generally well tolerated. This treatment regimen could provide patients with poor performance status a potent alternative to chemoradiation. This study has implications for the cost effectiveness of lung cancer therapy. Additional studies of long

  8. Hemoglobin Aggregation in Single Red Blood Cells of Sickle Cell Anemia

    Science.gov (United States)

    Nishio, Izumi; Tanaka, Toyoichi; Sun, Shao-Tang; Imanishi, Yuri; Tsuyoshi Ohnishi, S.

    1983-06-01

    A laser light scattering technique was used to observe the extent of hemoglobin aggregation in solitary red blood cells of sickle cell anemia. Hemoglobin aggregation was confirmed in deoxygenated cells. The light scattering technique can also be applied to cytoplasmic studies of any biological cell.

  9. Familial aggregation of urothelial cell carcinoma.

    NARCIS (Netherlands)

    Aben, K.K.H.; Witjes, J.A.; Schoenberg, M.P.; Hulsbergen-van de Kaa, C.A.; Verbeek, A.L.M.; Kiemeney, L.A.L.M.

    2002-01-01

    Urothelial cell carcinoma (UCC) is not considered to be a familial disease. Familial clustering of UCC was described in several case reports, however, some with an extremely early age at onset suggesting a genetic component. Epidemiological studies yielded inconsistent evidence of familial UCC, poss

  10. Tracking Hypoxic Signaling within Encapsulated Cell Aggregates

    OpenAIRE

    Skiles, Matthew L.; Sahai, Suchit; Blanchette, James O.

    2011-01-01

    In Diabetes mellitus type 1, autoimmune destruction of the pancreatic β-cells results in loss of insulin production and potentially lethal hyperglycemia. As an alternative treatment option to exogenous insulin injection, transplantation of functional pancreatic tissue has been explored1,2. This approach offers the promise of a more natural, long-term restoration of normoglycemia. Protection of the donor tissue from the host's immune system is required to prevent rejection and encapsulation is...

  11. Fractal Aggregation of Copper Particles using Electroless Cell

    Directory of Open Access Journals (Sweden)

    S.Q.Chishty

    2013-12-01

    Full Text Available A phenomenon In which the particles performing Brownian motion when hit the aggregates become the part of it is known as Diffusion limited aggregation (DLA, which produces a fractal shape. Experimental efforts are discussed through which some DLA shapes arc obtained. For this purpose different electrolytic solutions are used. Electro less cells are also designed and constructed using standard methods. The cells have to be flexible in the sense that changing of plates and solutions should be easier for photography. We used compounds of copper,. for growth of fractals. Within a very short time metallic dendrites appeared in the cell at different operating conditions. These images were photographed, while desired branching structures in copper sulphate solution were seen. Results thus obtained are compared with the growth of DLA.

  12. A role for amyloid in cell aggregation and biofilm formation.

    Directory of Open Access Journals (Sweden)

    Melissa C Garcia

    Full Text Available Cell adhesion molecules in Saccharomyces cerevisiae and Candida albicans contain amyloid-forming sequences that are highly conserved. We have now used site-specific mutagenesis and specific peptide perturbants to explore amyloid-dependent activity in the Candida albicans adhesin Als5p. A V326N substitution in the amyloid-forming region conserved secondary structure and ligand binding, but abrogated formation of amyloid fibrils in soluble Als5p and reduced cell surface thioflavin T fluorescence. When displayed on the cell surface, Als5p with this substitution prevented formation of adhesion nanodomains and formation of large cellular aggregates and model biofilms. In addition, amyloid nanodomains were regulated by exogenous peptides. An amyloid-forming homologous peptide rescued aggregation and biofilm activity of Als5p(V326N cells, and V326N substitution peptide inhibited aggregation and biofilm activity in Als5p(WT cells. Therefore, specific site mutation, inhibition by anti-amyloid peturbants, and sequence-specificity of pro-amyloid and anti-amyloid peptides showed that amyloid formation is essential for nanodomain formation and activation.

  13. Effects of osmolytes on protein folding and aggregation in cells.

    Science.gov (United States)

    Ignatova, Zoya; Gierasch, Lila M

    2007-01-01

    Nature has developed many strategies to ensure that the complex and challenging protein folding reaction occurs in vivo with adequate efficiency and fidelity for the success of the organism. Among the strategies widely employed in a huge range of species and cell types is the elaboration of small organic molecules called osmolytes that offset the potentially damaging effects of osmotic stress. While considerable knowledge has been gained in vitro regarding the influence of osmolytes on protein structure and folding, it is of great interest to probe the effects of osmolytes in cells. We have developed an in-cell fluorescent-labeling method that enables the study of protein stability and also protein aggregation in vivo. We utilize a genetically encoded tag called a tetra-Cys motif that binds specifically to a bis-arsenical fluorescein-based dye "FlAsH"; we inserted the tetra-Cys motif into a protein of interest in such a way that the FlAsH signal reported on the state of folding or aggregation of the protein. Then, we designed protocols to assess how various osmolytes influence the stability and propensity to aggregate of our protein of interest. These are described here. Not only are there potential biotechnological applications of osmolytes in the quest to produce greater quantities of well-folded proteins, but also osmolytes may serve as tools and points of departure for therapeutic intervention in protein folding and aggregation diseases. Having in vivo methods to analyze how osmolytes affect folding and aggregation enhances our ability to further these goals greatly.

  14. Phenomenological understanding of aggregation and dispersion of chemotactic cells

    CERN Document Server

    Iwasa, Masatomo

    2011-01-01

    We present a simple model that describes the motion of a single chemotactic cell exposed to a traveling wave of the chemoattractant. The model incorporates two types of responses to stimulation by the chemoattractant, i.e., change in polarity and change in motility of the cell. The periodic change in motility is assumed to be induced by the periodic stimulation by the chemoattractant on the basis of previous observations. Consequently, net migration of the cell occurs in a particular direction with respect to wave propagation, which explains the migration of Dictyostelium cells in aggregation processes. The difference between two time delays from the stimulation to the two responses and the wave frequency determined by the frequency of the secretion of the chemoattractant are important parameters that determine the direction of migration and the effective interaction between cells in a population. This result explains the dispersed state of a population of vegetative cells and cells in preaggregation without ...

  15. De-escalation treatment protocols for human papillomavirus-associated oropharyngeal squamous cell carcinoma: a systematic review and meta-analysis of current clinical trials.

    Science.gov (United States)

    Masterson, Liam; Moualed, Daniel; Liu, Zi Wei; Howard, James E F; Dwivedi, Raghav C; Tysome, James R; Benson, Richard; Sterling, Jane C; Sudhoff, Holger; Jani, Piyush; Goon, Peter K C

    2014-10-01

    Iatrogenic complications associated with current treatment protocols for oropharyngeal squamous cell carcinoma are noted to cause high rates of acute and chronic morbidity. The aims of this study are to provide an overview of the current de-escalation trials for human papillomavirus positive (HPV+) oropharyngeal carcinoma and to evaluate the evidence supporting improved response to treatment of patients within this viral cohort. This study reviewed all completed or in progress randomised controlled trials (RCTs) assessing clinical interventions for human papillomavirus-associated locally advanced oropharyngeal squamous cell carcinoma. We utilised a validated 'risk of bias' tool to assess study quality. We identified nine RCTs that met the full inclusion criteria for this review (all of which are currently on-going and will report from 2015 onwards). Five RCTs performed a post hoc analysis by HPV status, which allowed meta-analysis of 1130 patients. The data reveal a significant difference in overall survival (hazard ratio (HR) 0.49 [95% confidence interval (CI) 0.35-0.69]), loco-regional failure (HR 0.43 [95% CI 0.17-1.11]) and disease specific survival (0.41 [95% 0.3-0.56]) in favour of the HPV+ category. In considering de-escalation treatment protocols, nine studies are currently ongoing. Our meta-analysis provides strong evidence for an improved prognosis in the viral associated cohort when treated by platinum based chemotherapy in combination with radiotherapy or primary radiotherapy. So far, one trial (with moderate to high risk of bias) suggests a reduced survival outcome for the HPV+ population when using the epidermal growth factor receptor (EGFR) inhibitor cetuximab.

  16. Heparin promotes suspension adaptation process of CHO-TS28 cells by eliminating cell aggregation.

    Science.gov (United States)

    Li, Ling; Qin, Jun; Feng, Qiang; Tang, Hao; Liu, Rong; Xu, Liqing; Chen, Zhinan

    2011-01-01

    While heparin has been shown to eliminate cell aggregation in suspension adaptations of insect and HEK293 cells for virus-based cell cultures, the role of heparin in long period serum-free suspension adaptation of the anchorage-dependent Chinese hamster ovary (CHO) cell lines remains inconclusive. In this paper, we explore the potential application of heparin in suspension adaptation of CHO cell line which produces an anti-human chimeric antibody cHAb18. Heparin showed a concentration-dependent inhibition of CHO-TS28 cell-to-cell adhesion, with a significant inhibitory effect occurring when the concentration exceeded 250 μg/ml (P cell aggregation elimination role at all concentrations (P cell growth and antibody secretion, with the highest cell density ((99.83 ± 12.21) × 10(4) cells/ml, P = 0.034) and maximum antibody yield ((9.46 ± 0.94) mg/l, P cell aggregates were effectively dispersed by 250 μg/ml heparin and a single-cell suspension culture process was promoted. In suspension adapted CHO-TS28 cells, cell growth rates and specific antibody productivity were maintained; while antigen-binding activity improved slightly. Together, our results show that heparin may promote suspension adaptation of anchorage-depended CHO cells by resisting cell aggregation without reducing cell growth, antibody secretion, and antigen-binding activity.

  17. Aggregate Size Optimization in Microwells for Suspension-based Cardiac Differentiation of Human Pluripotent Stem Cells

    OpenAIRE

    Bauwens, Celine L.; Toms, Derek; Ungrin, Mark

    2016-01-01

    Cardiac differentiation of human pluripotent stems cells (hPSCs) is typically carried out in suspension cell aggregates. Conventional aggregate formation of hPSCs involves dissociating cell colonies into smaller clumps, with size control of the clumps crudely controlled by pipetting the cell suspension until the desired clump size is achieved. One of the main challenges of conventional aggregate-based cardiac differentiation of hPSCs is that culture heterogeneity and spatial disorganization l...

  18. Orthogonal cross-seeding: an approach to explore protein aggregates in living cells.

    Science.gov (United States)

    Hinz, Justyna; Gierasch, Lila M; Ignatova, Zoya

    2008-04-08

    Protein aggregation is associated with the pathology of many diseases, especially neurodegenerative diseases. A variety of structurally polymorphic aggregates or preaggregates including amyloid fibrils is accessible to any aggregating protein. Preaggregates are now believed to be the toxic culprits in pathologies rather than mature aggregates. Although clearly valuable, understanding the mechanism of formation and the structural characteristics of these prefibrillar species is currently lacking. We report here a simple new approach to map the nature of the aggregate core of transient aggregated species directly in the cell. The method is conceptually based on the highly discriminating ability of aggregates to recruit new monomeric species with equivalent molecular structure. Different soluble segments comprising parts of an amyloidogenic protein were transiently pulse-expressed in a tightly controlled, time-dependent manner along with the parent aggregating full-length protein, and their recruitment into the insoluble aggregate was monitored immunochemically. We used this approach to determine the nature of the aggregate core of the metastable aggregate species formed during the course of aggregation of a chimera containing a long polyglutamine repeat tract in a bacterial host. Strikingly, we found that different segments of the full-length protein dominated the aggregate core at different times during the course of aggregation. In its simplicity, the approach is also potentially amenable to screen also for compounds that can reshape the aggregate core and induce the formation of alternative nonamyloidogenic species.

  19. Escalation Practices in Automotive Development

    Directory of Open Access Journals (Sweden)

    Tomaž Jurejevčič

    2016-12-01

    Full Text Available Research Question (RQ: In automotive business many risk-involved situations occur and when detected, an escalation process takes place. Although defined and controlled by process guidelines and being supported by experts, escalation brings increased emotional pressure and stress for parties involved. Do escalation processes in automotive industry maintain all implied challenges? Purpose: The purpose of the article is to present current status of escalation processes and gaps between theory and practice cases. Results of the analysis are recommendations of good engineering practice derived also from actual experiences and learned lessons. Method: The method involves analysis of practical cases from automotive development process, lessons learned, anonymous survey of automotive engineers and classification of experiences. Results: Results of the survey have shown that the controlled escalation process for know-how related escalations is needed in order to establish the environment where the team is able to provide new, sometimes unconventional ideas for the problem to be solved. Organization: Presented recommendations and measures enable organization and managers to put the expertise and experiences of employees into action for problem solving during escalation. Originality: In this article some practices are presented that, although simple and some yet seen, with proper adjustment stemming from real life processes give a fruitful settlement of escalations in automotive development business.

  20. Expo 86: An Escalation Prototype.

    Science.gov (United States)

    Ross, Jerry; Staw, Barry M.

    1986-01-01

    British Columbia remained committed to its decision to host a world's fair (Expo 86) despite rapidly increasing deficit projections. Expo is examined as a prototypical example of the escalation of commitment. Theory is proposed that integrates determinants of escalation from several levels of analysis over time. (CJH)

  1. Recombinant T-Cell Receptor Ligand (RTL for Treatment of Multiple Sclerosis: A Double-Blind, Placebo-Controlled, Phase 1, Dose-Escalation Study

    Directory of Open Access Journals (Sweden)

    Vijayshree Yadav

    2012-01-01

    Full Text Available Background. Recombinant T-cell receptor ligand 1000 (RTL1000 is a single-chain protein construct containing the outer two domains of HLA-DR2 linked to myelin-oligodendrocyte-glycoprotein- (MOG- 35–55 peptide. Analogues of RTL1000 induce T-cell tolerance, reverse clinical and histological disease, and promote repair in experimental autoimmune encephalomyelitis (EAE in DR2 transgenic, C57BL/6, and SJL/J mice. Objective. Determining the maximum tolerated dose, safety, and tolerability of RTL1000 in multiple sclerosis (MS subjects. Methods. This was a multicenter, Phase I dose-escalation study in HLA-DR2+ MS subjects. Consecutive cohorts received RTL1000 doses of 2, 6, 20, 60, 200, and 100 mg, respectively. Subjects within each cohort randomly received a single intravenous infusion of RTL1000 or placebo at a 4 : 2 ratio. Safety monitoring included clinical, laboratory, and brain magnetic resonance imaging (MRI evaluations. Results. Thirty-four subjects completed the protocol. All subjects tolerated the 2–60 mg doses of RTL1000. Doses ≥100 mg caused hypotension and diarrhea in 3 of 4 subjects, leading to discontinuation of further enrollment. Conclusions. The maximum tolerated dose of RTL1000 in MS subjects is 60 mg, comparable to effective RTL doses in EAE. RTL1000 is a novel approach for MS treatment that may induce immunoregulation without immunosuppression and promote neural repair.

  2. Cell and organ printing 2: fusion of cell aggregates in three-dimensional gels.

    Science.gov (United States)

    Boland, Thomas; Mironov, Vladimir; Gutowska, Anna; Roth, Elisabeth A; Markwald, Roger R

    2003-06-01

    We recently developed a cell printer (Wilson and Boland, 2003) that enables us to place cells in positions that mimic their respective positions in organs. However, this technology was limited to the printing of two-dimensional (2D) tissue constructs. Here we describe the use of thermosensitive gels to generate sequential layers for cell printing. The ability to drop cells on previously printed successive layers provides a real opportunity for the realization of three-dimensional (3D) organ printing. Organ printing will allow us to print complex 3D organs with computer-controlled, exact placing of different cell types, by a process that can be completed in several minutes. To demonstrate the feasibility of this novel technology, we showed that cell aggregates can be placed in the sequential layers of 3D gels close enough for fusion to occur. We estimated the optimum minimal thickness of the gel that can be reproducibly generated by dropping the liquid at room temperature onto a heated substrate. Then we generated cell aggregates with the corresponding (to the minimal thickness of the gel) size to ensure a direct contact between printed cell aggregates during sequential printing cycles. Finally, we demonstrated that these closely-placed cell aggregates could fuse in two types of thermosensitive 3D gels. Taken together, these data strongly support the feasibility of the proposed novel organ-printing technology.

  3. Spherical TiO2 aggregates with different building units for dye-sensitized solar cells.

    Science.gov (United States)

    Liu, Zhaohui; Su, Xunjia; Hou, Genliang; Bi, Song; Xiao, Zhou; Jia, Haipeng

    2013-09-07

    Tailoring the architectures of spherical TiO2 aggregates is crucial to obtain superior photovoltaic properties and promote their application in dye-sensitized solar cells (DSSCs). Herein, we synthesized spherical TiO2 aggregates using different building units, including nanocrystallites, nanorods, nanosheets, and nanotubes, via a hydrothermal method, and studied the effect of the building units on the performances of DSSCs. The aggregates assembled by uniform nanosheet and nanotube building units were synthesized with the use of spherical TiO2 nanorod aggregates as titanium sources in an alkaline hydrothermal reaction. Compared with TiO2 nanoparticles, the spherical TiO2 aggregates possess higher surface area, more efficient light scattering ability, and better electron transport properties. Among the four types of spherical TiO2 aggregates; the nanorod, nanotube, and nanosheet aggregates demonstrate better electron transport properties than the nanocrystallite aggregates; the nanotube and nanosheet aggregates exhibit more efficient light scattering than the nanocrystallite and nanorod aggregates; and the nanotube aggregates show the highest surface area. Thus the DSSC based on nanotube aggregates exhibited the highest energy conversion efficiency of 7.48%, which is 16.0%, 9.7%, and 19.5% higher than those of the DSSCs based on the nanosheet, nanorod, and nanocrystallite aggregates, respectively.

  4. Non-cell autonomous cell death caused by transmission of Huntingtin aggregates in Drosophila.

    Science.gov (United States)

    Babcock, Daniel T; Ganetzky, Barry

    2015-01-01

    Recent evidence indicates that protein aggregates can spread between neurons in several neurodegenerative diseases but much remains unknown regarding the underlying mechanisms responsible for this spreading and its role in disease progression. We recently demonstrated that mutant Huntingtin aggregates spread between cells within the Drosophila brain resulting in non-cell autonomous loss of a pair of large neurons in the posterior protocerebrum. However, the full extent of neuronal loss throughout the brain was not determined. Here we examine the effects of driving expression of mutant Huntingtin in Olfactory Receptor Neurons (ORNs) by using a marker for cleaved caspase activity to monitor neuronal apoptosis as a function of age. We find widespread caspase activity in various brain regions over time, demonstrating that non-cell autonomous damage is widespread. Improved understanding of which neurons are most vulnerable and why should be useful in developing treatment strategies for neurodegenerative diseases that involve transcellular spreading of aggregates.

  5. Screening and analysis of differentially expressed genes of dermal papillae cells with aggregative behavior

    Institute of Scientific and Technical Information of China (English)

    宋志强; 郝飞; 杨卫兵; 王继文; 邹锋

    2004-01-01

    Objective: To screen and clone differentially expressed genes of dermal papillae cells (DPC) with aggregative behavior, and to explore the molecular mechanism of their aggregation. Methods: Total RNAs were extracted from DPC with and without aggregative behavior and double strand cDNAs were synthesized by using SMART cDNA synthesis, respectively. The cDNA fragments of differentially expressed genes in DPCs with aggregative behavior were isolated by suppression subtractive hybridization. Positive clones were screened by PCR method and verified by cDNA dot blot, Northern blot and then analyzed through homologous retrieving. Results: A subtractive cDNA library of DPC with aggregative behavior has been successfully constructed. The result of screening and cloning of the library showed that, DPC with aggregative behavior could expresse genes related to homologous aggregation, proliferation and cycle control, including known genes (capping protein, paladin, vascular endothelial growth factor), hematopoietic stem/progenitor cells (HSPC) related clone (HSPC011 and HSPC016) and a new gene. Conclusion: The construction of subtracted library of DPC lays solid foundation for screening and cloning new and specific genes related to aggregative behavior of DPC. Several genes might be cooperatively involved in the homologous aggregation, proliferation and cycle control of DPC. Among these genes, capping protein and palladin might be closely related to the aggregative behavior of dermal papilla cells, and VEGF and HSPC related clone would be responsible for the status of higher proliferation of dermal papilla cells.

  6. Geometrical Aspects During Formation of Compact Aggregates of Red Blood Cells

    Directory of Open Access Journals (Sweden)

    Cardoso A.V.

    2002-01-01

    Full Text Available In the past forty years considerable progress has been achieved on the knowledge of human blood as a non-Newtonian shear-thinning suspension, whose initial state, that is at rest (stasis or at very low shear rates, has a gel-like internal structure which is destroyed as shear stress increases. The main goal of this communication is to describe the role of geometrical aspects during RBC (red blood cell aggregate formation, growth and compaction on naturally aggregate (porcine blood and non-aggregate (bovine blood samples. We consider how these aspects coupled with tension equilibrium are decisive to transform red cell linear roleaux to three-dimensional aggregates or clusters. Geometrical aspects are also crucial on the compaction of red blood cell aggregates. These densely packed aggregates could precipitate out of blood- either as dangerous deposits on arterial walls, or as clots which travel in suspension until they block some crucial capillary.

  7. Escalation of the Space Domain

    Science.gov (United States)

    2015-04-01

    spacepower – what is meant by spacepower and how might its elements be made available for escalation. Chapter 2 Escalation 101 “We sleep safely...its instruments of national power to change the forthcoming behavior of an adversary.21 There are two distinct types of coercion: punishment and...are similar in nature and application to those seen in science fiction moves or on television (i.e., Star Trek) that can provide direct kinetic

  8. Understanding behavior in escalation situations.

    Science.gov (United States)

    Staw, B M; Ross, J

    1989-10-13

    Everyday observation reveals that both individuals and organizations often become overly committed to losing courses of action; in a sense, throwing good money after bad. More than 10 years of research on this escalation problem shows that persistence is associated with at least four major clases of determinants: project, psychological, social, and organizational variables. The influence of these four sets of variables evolves over time, forming a dynamic model of behavior in escalation situations.

  9. Dye-sensitized solar cell employing zinc oxide aggregates grown in the presence of lithium

    Science.gov (United States)

    Zhang, Qifeng; Cao, Guozhong

    2013-10-15

    Provided are a novel ZnO dye-sensitized solar cell and method of fabricating the same. In one embodiment, deliberately added lithium ions are used to mediate the growth of ZnO aggregates. The use of lithium provides ZnO aggregates that have advantageous microstructure, morphology, crystallinity, and operational characteristics. Employing lithium during aggregate synthesis results in a polydisperse collection of ZnO aggregates favorable for porosity and light scattering. The resulting nanocrystallites forming the aggregates have improved crystallinity and more favorable facets for dye molecule absorption. The lithium synthesis improves the surface stability of ZnO in acidic dyes. The procedures developed and disclosed herein also help ensure the formation of an aggregate film that has a high homogeneity of thickness, a high packing density, a high specific surface area, and good electrical contact between the film and the fluorine-doped tin oxide electrode and among the aggregate particles.

  10. Patterning processes in aggregates of Hydra cells visualized with the monoclonal antibody, TS19.

    Science.gov (United States)

    Sato, M; Bode, H R; Sawada, Y

    1990-10-01

    The monoclonal antibody, TS19, (Heimfeld et al., 1985), labels the apical surface of ectodermal epithelial cells of tentacles and lower peduncles in Hydra. To investigate the patterning process in a tissue whose original pattern was completely destroyed, the TS19 staining pattern was examined in developing aggregates of Hydra cells. Two types of aggregates were prepared. G-aggregates were made from tissue of the gastric portion of animals and RG-aggregates from gastric tissue allowed to regenerate for 24 hr before making aggregates. G-aggregates were initially TS19-negative, and later dim and uniformly TS19-positive. Thereafter, TS19 staining broke up into brightly stained and unstained regions. The brightly staining regions developed into head or foot structures. The TS19 pattern in RG-aggregates developed differently. Since the initial aggregates contained cells of regenerating tips, they started with TS19-positive cells as well as TS19-negative cells. The numbers of brightly staining TS19-positive cells increased with time. Some patches of these cells developed into head or foot structures, while others did not. These results and a simulation using a reaction-diffusion model suggest that the changes in activation levels affected the temporal changes in the pattern of TS19 staining, and that the de novo pattern formation in hydra can be explained in terms of a process involving activation and inhibition properties.

  11. Characterization of circulating tumor cell aggregates identified in patients with epithelial tumors

    Science.gov (United States)

    Cho, Edward H.; Wendel, Marco; Luttgen, Madelyn; Yoshioka, Craig; Marrinucci, Dena; Lazar, Daniel; Schram, Ethan; Nieva, Jorge; Bazhenova, Lyudmila; Morgan, Alison; Ko, Andrew H.; Korn, W. Michael; Kolatkar, Anand; Bethel, Kelly; Kuhn, Peter

    2012-02-01

    Circulating tumor cells (CTCs) have been implicated as a population of cells that may seed metastasis and venous thromboembolism (VTE), two major causes of mortality in cancer patients. Thus far, existing CTC detection technologies have been unable to reproducibly detect CTC aggregates in order to address what contribution CTC aggregates may make to metastasis or VTE. We report here an enrichment-free immunofluorescence detection method that can reproducibly detect and enumerate homotypic CTC aggregates in patient samples. We identified CTC aggregates in 43% of 86 patient samples. The fraction of CTC aggregation was investigated in blood draws from 24 breast, 14 non-small cell lung, 18 pancreatic, 15 prostate stage IV cancer patients and 15 normal blood donors. Both single CTCs and CTC aggregates were measured to determine whether differences exist in the physical characteristics of these two populations. Cells contained in CTC aggregates had less area and length, on average, than single CTCs. Nuclear to cytoplasmic ratios between single CTCs and CTC aggregates were similar. This detection method may assist future studies in determining which population of cells is more physically likely to contribute to metastasis and VTE.

  12. Trehalose suppresses antibody aggregation during the culture of Chinese hamster ovary cells.

    Science.gov (United States)

    Onitsuka, Masayoshi; Tatsuzawa, Miki; Asano, Ryutaro; Kumagai, Izumi; Shirai, Akihiro; Maseda, Hideaki; Omasa, Takeshi

    2014-05-01

    The aggregation of therapeutic antibodies during the manufacturing process is problematic because of the potential risks posed by the aggregates, such as an unexpected immune response. One of the hallmark effects of trehalose, a disaccharide consisting of two alpha-glucose units, is as a chemical chaperone with anti-aggregation activity. In this study, Chinese hamster ovary (CHO) cell line producing a diabody-type bispecific antibody were cultured in medium containing trehalose and the aggregation of the secreted proteins during the culture process was analyzed. An analysis of the various forms of the antibody (monomeric, dimeric, and large aggregates) showed that trehalose decreased the relative content of large aggregates by two thirds. The aggregation kinetics indicated that trehalose directly inhibited the polymerization and aggregation steps in a nucleation-dependent aggregation mechanism. Moreover, both specific and volumetric antibody production were increased in CHO cells cultured in trehalose-containing medium. Thus, the addition of trehalose to recombinant CHO cell cultures would offer a practical strategy for quality improvement in the production of therapeutic antibodies.

  13. Photodynamic treatment of red blood cell concentrates for virus inactivation enhances red blood cell aggregation: protection with antioxidants.

    Science.gov (United States)

    Ben-Hur, E; Barshtein, G; Chen, S; Yedgar, S

    1997-10-01

    Photodynamic treatment (PDT) using phthalocyanines and red light appears to be a promising procedure for decontamination of red blood cell (RBC) concentrates for transfusion. A possible complication of this treatment may be induced aggregation of RBC. The production of RBC aggregates was measured with a novel computerized cell flow properties analyzer (CFA). The PDT of RBC concentrates with sulfonated aluminum phthalocyanine (AIPcS4) and the silicon phthalocyanine Pc 4 under virucidal conditions markedly enhanced RBC aggregation and higher shear stress was required to disperse these aggregates. The clusters of cells were huge and abnormally shaped, unlike the rouleaux formed by untreated RBC. This aggregation was prevented when a mixture of antioxidants was included during PDT. Addition of the antioxidants after PDT reduced aggregation only partially. It is concluded that inclusion of antioxidants during PDT of RBC concentrates prior to transfusion may reduce or eliminate the hemodynamic risk that the virucidal treatment may present to the recipient.

  14. Detection and characterization of red blood cell (RBC) aggregation with photoacoustics

    Science.gov (United States)

    Hysi, Eno; Saha, Ratan K.; Rui, Min; Kolios, Michael C.

    2012-02-01

    Red blood cells (RBCs) aggregate in the presence of increased plasma fibrinogen and low shear forces during blood flow. RBC aggregation has been observed in deep vein thrombosis, sepsis and diabetes. We propose using photoacoustics (PA) as a non-invasive imaging modality to detect RBC aggregation. The theoretical and experimental feasibility of PA for detecting and characterizing aggregation was assessed. A simulation study was performed to generate PA signals from non-aggregated and aggregated RBCs using a frequency domain approach and to study the PA signals' dependence on hematocrit and aggregate size. The effect of the finite bandwidth nature of transducers on the PA power spectra was also investigated. Experimental confirmation of theoretical results was conducted using porcine RBC samples exposed to 1064 nm optical wavelength using the Imagio Small Animal PA imaging system (Seno Medical Instruments, Inc., San Antonio, TX). Aggregation was induced with Dextran-70 (Sigma-Aldrich, St. Louis, MO) and the effect of hematocrit and aggregation level was investigated. The theoretical and experimental PA signal amplitude increased linearly with increasing hematocrit. The theoretical dominant frequency content of PA signals shifted towards lower frequencies (<30 MHz) and 9 dB enhancements in spectral power were observed as the size of aggregates increased compared to non-aggregating RBCs. Calibration of the PA spectra with the transducer response obtained from a 200 nm gold film was performed to remove system dependencies. Analysis of the spectral parameters from the calibrated spectra suggested that PA can assess the degree of aggregation at multiple hematocrit and aggregation levels.

  15. Using Generalized Equivalent Uniform Dose Atlases to Combine and Analyze Prospective Dosimetric and Radiation Pneumonitis Data From 2 Non-Small Cell Lung Cancer Dose Escalation Protocols

    Energy Technology Data Exchange (ETDEWEB)

    Liu Fan; Yorke, Ellen D. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Belderbos, Jose S.A.; Borst, Gerben R. [The Netherlands Cancer Institute, Antoni Van Leeuwenhoek Hospital, Amsterdam (Netherlands); Rosenzweig, Kenneth E. [Mount Sinai School of Medicine, New York, New York (United States); Lebesque, Joos V. [The Netherlands Cancer Institute, Antoni Van Leeuwenhoek Hospital, Amsterdam (Netherlands); Jackson, Andrew, E-mail: jacksona@mskcc.org [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2013-01-01

    Purpose: To demonstrate the use of generalized equivalent uniform dose (gEUD) atlas for data pooling in radiation pneumonitis (RP) modeling, to determine the dependence of RP on gEUD, to study the consistency between data sets, and to verify the increased statistical power of the combination. Methods and Materials: Patients enrolled in prospective phase I/II dose escalation studies of radiation therapy of non-small cell lung cancer at Memorial Sloan-Kettering Cancer Center (MSKCC) (78 pts) and the Netherlands Cancer Institute (NKI) (86 pts) were included; 10 (13%) and 14 (17%) experienced RP requiring steroids (RPS) within 6 months after treatment. gEUD was calculated from dose-volume histograms. Atlases for each data set were created using 1-Gy steps from exact gEUDs and RPS data. The Lyman-Kutcher-Burman model was fit to the atlas and exact gEUD data. Heterogeneity and inconsistency statistics for the fitted parameters were computed. gEUD maps of the probability of RPS rate {>=}20% were plotted. Results: The 2 data sets were homogeneous and consistent. The best fit values of the volume effect parameter a were small, with upper 95% confidence limit around 1.0 in the joint data. The likelihood profiles around the best fit a values were flat in all cases, making determination of the best fit a weak. All confidence intervals (CIs) were narrower in the joint than in the individual data sets. The minimum P value for correlations of gEUD with RPS in the joint data was .002, compared with P=.01 and .05 for MSKCC and NKI data sets, respectively. gEUD maps showed that at small a, RPS risk increases with gEUD. Conclusions: The atlas can be used to combine gEUD and RPS information from different institutions and model gEUD dependence of RPS. RPS has a large volume effect with the mean dose model barely included in the 95% CI. Data pooling increased statistical power.

  16. Understanding Behavior in Escalation Situations.

    Science.gov (United States)

    Staw, Barry M.; Ross, Jerry

    1989-01-01

    The escalation of commitment has been variously labeled the psychology of entrapment, the sunk cost effect, and the too-much-invested-to-quit syndrome. This article reviews the state of research and describes four major determinants: project; psychological; social; and organizational variables. A model is provided. (YP)

  17. An effect of glycoprotein IIb/IIIa inhibitors on the kinetics of red blood cells aggregation.

    Science.gov (United States)

    Sokolova, Irina A; Muravyov, Alexei V; Khokhlova, Maria D; Rikova, Sofya Yu; Lyubin, Evgeny V; Gafarova, Marina A; Skryabina, Maria N; Fedyanin, Angrey A; Kryukova, Darya V; Shahnazarov, Alexander A

    2014-01-01

    The reversible aggregation of red blood cells (RBCs) continues to be of the basic science and clinical interest. Recently it has been reported about a specific binding between fibrinogen and unknown erythrocyte glycoprotein receptors. The aim of this study was to investigate whether the red blood cell aggregation (RBCA) include the cell-cell interaction using the membrane receptors that bind such ligands as fibrinogen or fibronectin. To test this hypothesis the RBCs were incubated with monafram - the drug of the monoclonal antibodies against glycoprotein (GP) IIb/IIIa, with the GPIIb-IIIa receptor antagonist tirofiban, epifibatide and with the fibrinogen inhibiting peptide. It has been found that the RBC incubation with monafram resulted in a marked RBCA decrease mainly in persons with high level of aggregation. Another research session has shown that RBC incubation with fibronectin was accompanied by a significant RBCA rise. The monafram addition to red cell incubation medium resulted in a significant RBCA lowering. The cell incubation with tirofiban and epifibatide issued in RBCA decrease. The similar results were obtained when RBCs were incubated with the fibrinogen inhibiting peptide. Although monafram, tirofiban, eptifibatide and the fibrinogen inhibiting peptide were related to fibrinogen function they didn't inhibit RBCA completely. Therefore, under moderate and low red blood cell aggregation the cell binding is probably related to nonspecific mode. It seems evident that the specific and nonspecific modes of red blood cell aggregate formation could co-exist. Additional theoretical and experimental investigations in this area are needed.

  18. Improvement and enhancement of antibladder carcinoma cell effects of heteronemin by the nanosized hyaluronan aggregation

    Directory of Open Access Journals (Sweden)

    Huang HH

    2016-03-01

    Full Text Available Han Hsiang Huang,1 Shyh Ming Kuo,2 Yi-Jhen Wu,2 Jui-Hsin Su3 1Department of Veterinary Medicine, National Chiayi University, Chiayi City, 2Department of Biomedical Engineering, I-Shou University, Kaohsiung City, 3National Museum of Marine Biology and Aquarium, Pingtung, Taiwan Abstract: The effects against tumors exerted by marine active compounds have been highlighted and investigated. Polymeric nanoparticles made from biodegradable and biocompatible molecules such as hyaluronan (HA and chitosan (CHI are able to aggregate the compounds to enhance their activities against tumor cells and reduce the toxicity on normal cells. Here, we extensively examined the antitumor activities and the mechanisms of HA/CHI nanoparticles-aggregated heteronemin (HET extracted from the sponge Hippospongia sp. The half-maximal inhibitory concentration (IC50 of pure HET toward T24 bladder carcinoma cells is ~0.28 µg/mL. Pure HET from 0.2 to 0.8 µg/mL and HA nanoparticles-aggregated HET at 0.1 and 0.2 µg/mL significantly reduced T24 cell viability. Compared to pure HET, HA nanoparticles/HET aggregates showed much weaker viability-inhibitory effects on L929 normal fibroblasts. HET dose-dependently suppressed cancer cell migration as HA/CHI nanoparticles-aggregated HET displayed stronger migration-inhibitory effects than pure HET. Flow cytometric analysis showed that pure HET increased early/total apoptosis and JC-1 monomer fluorescence, while HA/CHI nanoparticles-aggregated HET induced higher apoptosis and JC-1 monomer rates than pure HET, suggesting that aggregation of HA nanoparticles offers HET stronger apoptosis-inducing capacity through mitochondrial depolarization. Western blot analysis showed that HA nanoparticles-aggregated HET further increased mitochondrial-associated, caspase-dependent and caspase-independent, as well as endoplasmic reticulum stress-related factors in comparison with pure HET. These data indicated that pure HET possesses cytotoxic

  19. Glycosylation analysis of an aggregated antibody produced by Chinese hamster ovary cells in bioreactor culture.

    Science.gov (United States)

    Onitsuka, Masayoshi; Kawaguchi, Akira; Asano, Ryutaro; Kumagai, Izumi; Honda, Kohsuke; Ohtake, Hisao; Omasa, Takeshi

    2014-05-01

    N-Glycosylation of therapeutic antibodies contributes not only to their biological function, but also to their stability and tendency to aggregate. Here, we investigated the impact of the glycosylation status of an aggregated antibody that accumulated during the bioreactor culture of Chinese hamster ovary cells. High-performance liquid chromatography analysis showed that there was no apparent difference in the glycosylation patterns of monomeric, dimeric, and large aggregated forms of the antibody. In contrast, lectin binding assays, which enable the total amounts of specific sugar residues to be detected, showed that both galactose and fucose residues in dimers and large aggregates were reduced to 70-80% of the amount in monomers. These results strongly suggest that the lack of N-linked oligosaccharides, a result of deglycosylation or aglycosylation, occurred in a proportion of the dimeric and large aggregated components. The present study demonstrates that glycosylation heterogeneities are a potential cause of antibody aggregation in cell culture of Chinese hamster ovary cells, and that the lack of N-glycosylation promotes the formation of dimers and finally results in large aggregates.

  20. Photometric measurements of red blood cell aggregation: light transmission versus light reflectance.

    Science.gov (United States)

    Baskurt, Oguz K; Uyuklu, Mehmet; Hardeman, Max R; Meiselman, Herbert J

    2009-01-01

    Red blood cell (RBC) aggregation is the reversible and regular clumping in the presence of certain macromolecules. This is a clinically important phenomenon, being significantly enhanced in the presence of acute phase reactants (e.g., fibrinogen). Both light reflection (LR) and light transmission (LT) from or through thin layers of RBC suspensions during the process of aggregation are accepted to reflect the time course of aggregation. It has been recognized that the time courses of LR and LT might be different from each other. We aim to compare the RBC aggregation measurements based on simultaneous recordings of LR and LT. The results indicate that LR during RBC aggregation is characterized by a faster time course compared to simultaneously recorded LT. This difference in time course of LR and LT is reflected in the calculated parameters reflecting the overall extent and kinetics of RBC aggregation. Additionally, the power of parameters calculated using LR and LT time courses in detecting a given difference in aggregation are significantly different from each other. These differences should be taken into account in selecting the appropriate calculated parameters for analyzing LR or LT time courses for the assessment of RBC aggregation.

  1. Oxygen transport and stem cell aggregation in stirred-suspension bioreactor cultures.

    Directory of Open Access Journals (Sweden)

    Jincheng Wu

    Full Text Available Stirred-suspension bioreactors are a promising modality for large-scale culture of 3D aggregates of pluripotent stem cells and their progeny. Yet, cells within these clusters experience limitations in the transfer of factors and particularly O2 which is characterized by low solubility in aqueous media. Cultured stem cells under different O2 levels may exhibit significantly different proliferation, viability and differentiation potential. Here, a transient diffusion-reaction model was built encompassing the size distribution and ultrastructural characteristics of embryonic stem cell (ESC aggregates. The model was coupled to experimental data from bioreactor and static cultures for extracting the effective diffusivity and kinetics of consumption of O2 within mouse (mESC and human ESC (hESC clusters. Under agitation, mESC aggregates exhibited a higher maximum consumption rate than hESC aggregates. Moreover, the reaction-diffusion model was integrated with a population balance equation (PBE for the temporal distribution of ESC clusters changing due to aggregation and cell proliferation. Hypoxia was found to be negligible for ESCs with a smaller radius than 100 µm but became appreciable for aggregates larger than 300 µm. The integrated model not only captured the O2 profile both in the bioreactor bulk and inside ESC aggregates but also led to the calculation of the duration that fractions of cells experience a certain range of O2 concentrations. The approach described in this study can be employed for gaining a deeper understanding of the effects of O2 on the physiology of stem cells organized in 3D structures. Such frameworks can be extended to encompass the spatial and temporal availability of nutrients and differentiation factors and facilitate the design and control of relevant bioprocesses for the production of stem cell therapeutics.

  2. Nestin+cells forming spheroids aggregates resembling tumorspheres in experimental ENU-induced gliomas.

    Science.gov (United States)

    García-Blanco, Alvaro; Bulnes, Susana; Pomposo, Iñigo; Carrasco, Alex; Lafuente, José Vicente

    2016-12-01

    Nestin+cells from spheroid aggregates display typical histopathological features compatible with cell stemness. Nestin and CD133+cells found in glioblastomas, distributed frequently around aberrant vessels, are considered as potential cancer stem cells. They are possible targets for antitumoral therapy because they lead the tumorigenesis, invasiveness and angiogenesis. However, little is known about their role and presence in low-grade gliomas. The aim of this work is to localize and characterize the distribution of these cells inside tumors during the development of experimental endogenous glioma. For this study, a single dose of Ethyl-nitrosourea was injected into pregnant rats. Double immunofluorescences were performed in order to identify stem-like and differentiated cells. Low-grade gliomas display Nestin+cells distributed throughout the tumor. More malignant gliomas show, in addition to that, a perivascular location with some Nestin+cells co-expressing CD133 or VEGF, and the intratumoral spheroid aggregates of Nestin/CD133+cells. These structures are encapsulated by well-differentiated VEGF/GFAP+cells. Spheroid aggregates increase in size in the most malignant stages. Spheroid aggregates have morphological and phenotypic similarities to in vitro neurospheres and could be an in vivo analogue of them. These arrangements could be a reservoir of undifferentiated cells formed to escape adverse microenvironments.

  3. Cathepsin G Induces Cell Aggregation of Human Breast Cancer MCF-7 Cells via a 2-Step Mechanism: Catalytic Site-Independent Binding to the Cell Surface and Enzymatic Activity-Dependent Induction of the Cell Aggregation

    Directory of Open Access Journals (Sweden)

    Riyo Morimoto-Kamata

    2012-01-01

    Full Text Available Neutrophils often invade various tumor tissues and affect tumor progression and metastasis. Cathepsin G (CG is a serine protease secreted from activated neutrophils. Previously, we have shown that CG induces the formation of E-cadherin-mediated multicellular spheroids of human breast cancer MCF-7 cells; however, the molecular mechanisms involved in this process are unknown. In this study, we investigated whether CG required its enzymatic activity to induce MCF-7 cell aggregation. The cell aggregation-inducing activity of CG was inhibited by pretreatment of CG with the serine protease inhibitors chymostatin and phenylmethylsulfonyl fluoride. In addition, an enzymatically inactive S195G (chymotrypsinogen numbering CG did not induce cell aggregation. Furthermore, CG specifically bound to the cell surface of MCF-7 cells via a catalytic site-independent mechanism because the binding was not affected by pretreatment of CG with serine protease inhibitors, and cell surface binding was also detected with S195G CG. Therefore, we propose that the CG-induced aggregation of MCF-7 cells occurs via a 2-step process, in which CG binds to the cell surface, independently of its catalytic site, and then induces cell aggregation, which is dependent on its enzymatic activity.

  4. Is Intermediate Radiation Dose Escalation With Concurrent Chemotherapy for Stage III Non–Small-Cell Lung Cancer Beneficial? A Multi-Institutional Propensity Score Matched Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, George, E-mail: george.rodrigues@lhsc.on.ca [London Health Sciences Centre, London, Ontario (Canada); Oberije, Cary [MAASTRO Clinic, Maastricht (Netherlands); Senan, Suresh [VU University Medical Center, Amsterdam (Netherlands); Tsujino, Kayoko [Hyogo Cancer Center, Akashi (Japan); Wiersma, Terry [MAASTRO Clinic, Maastricht (Netherlands); Moreno-Jimenez, Marta [Universidad de Navarra, Pamplona (Spain); Kim, Tae Hyun [National Cancer Center, Goyang-si, Gy eonggi (Korea, Republic of); Marks, Lawrence B. [University of North Carolina, Chapel Hill, North Carolina (United States); Rengan, Ramesh [University of Washington, Seattle, Washington (United States); De Petris, Luigi [Karolinska University Hospital, Stockholm (Sweden); Ramella, Sara [Campus Bio-Medico University, Rome (Italy); DeRuyck, Kim [Ghent University, Ghent (Belgium); De Dios, Núria Rodriguez [Universidad Pompeu Fabra, Barcelona (Spain); Warner, Andrew [London Health Sciences Centre, London, Ontario (Canada); Bradley, Jeffrey D. [Washington University School of Medicine, St. Louis, Missouri (United States); Palma, David A. [London Health Sciences Centre, London, Ontario (Canada)

    2015-01-01

    Purpose: The clinical benefits and risks of dose escalation (DE) for stage III non–small-cell lung cancer (NSCLC) remain uncertain despite the results from Radiation Therapy Oncology Group (RTOG) protocol 0617. There is significant heterogeneity of practice, with many clinicians prescribing intermediate dose levels between the 0617 study arms of 60 and 74 Gy. This study investigated whether this strategy is associated with any survival benefits/risks by analyzing a large multi-institutional database. Methods and Materials: An individual patient database of stage III NSCLC patients treated with radical intent concurrent chemoradiation therapy was created (13 institutions, n=1274 patients). Patients were divided into 2 groups based on tumor Biological Effective Dose at 10 Gy (BED 10): those receiving standard dose (SD; n=552), consisting of 72Gy ≤ BED 10 ≤ 76.8 Gy (eg 60-64 Gy/30-32 fractions [fr]), and those receiving intermediate dose (ID; n=497), consisting of 76.8Gy < BED 10 < 100.8 Gy (eg >64 Gy/32 fr and <74 Gy/37 fr), with lower-dose patients (n=225) excluded from consideration. Patients were then matched using propensity scores, leading to 2 matched groups of 196 patients. Outcomes were compared using various statistics including interquartile range (IQR), Kaplan-Meier curves, and adjusted Cox regression analysis. Results: Matched groups were found to be balanced except for N stage (more N3 disease in SD), median treatment year (SD in 2003; ID in 2007), platinum and taxane chemotherapy (SD in 28%; ID in 39%), and median follow-up (SD were 89 months; ID were 40 months). Median dose fractionation was 60 Gy/30 fr in SD (BED 10 IQR: 72.0-75.5 Gy) and 66 Gy/33 fr (BED 10 IQR: 78.6-79.2 Gy) in ID. Survival curves for SD and ID matched cohorts were statistically similar (P=.27); however, a nonstatistically significant trend toward better survival for ID was observed after 15 months (median survival SD: 19.3 months; ID: 21.0

  5. Sponge cell reaggregation: Cellular structure and morphogenetic potencies of multicellular aggregates.

    Science.gov (United States)

    Lavrov, Andrey I; Kosevich, Igor A

    2016-02-01

    Sponges (phylum Porifera) are one of the most ancient extant multicellular animals and can provide valuable insights into origin and early evolution of Metazoa. High plasticity of cell differentiations and anatomical structure is characteristic feature of sponges. Present study deals with sponge cell reaggregation after dissociation as the most outstanding case of sponge plasticity. Dynamic of cell reaggregation and structure of multicellular aggregates of three demosponge species (Halichondria panicea (Pallas, 1766), Haliclona aquaeductus (Sсhmidt, 1862), and Halisarca dujardinii Johnston, 1842) were studied. Sponge tissue dissociation was performed mechanically. Resulting cell suspensions were cultured at 8-10°C for at least 5 days. Structure of multicellular aggregates was studied by light, transmission and scanning electron microscopy. Studied species share common stages of cell reaggregation-primary multicellular aggregates, early-stage primmorphs and primmorphs, but the rate of reaggregation varies considerably among species. Only cells of H. dujardinii are able to reconstruct functional and viable sponge after primmorphs formation. Sponge reconstruction in this species occurs due to active cell locomotion. Development of H. aquaeductus and H. panicea cells ceases at the stages of early primmorphs and primmorphs, respectively. Development of aggregates of these species is most likely arrested due to immobility of the majority of cells inside them. However, the inability of certain sponge species to reconstruct functional and viable individuals during cell reaggregation may be not a permanent species-specific characteristic, but depends on various factors, including the stage of the life cycle and experimental conditions.

  6. Effect of polymer aggregation on the open circuit voltage in organic photovoltaic cells: aggregation-induced conjugated polymer gel and its application for preventing open circuit voltage drop.

    Science.gov (United States)

    Kim, Bong-Gi; Jeong, Eun Jeong; Park, Hui Joon; Bilby, David; Guo, L Jay; Kim, Jinsang

    2011-03-01

    To investigate the structure-dependent aggregation behavior of conjugated polymers and the effect of aggregation on the device performance of conjugated polymer photovoltaic cells, new conjugated polymers (PVTT and CN-PVTT) having the same regioregularity but different intermolecular packing were prepared and characterized by means of UV-vis spectroscopy and atomic force microscopy (AFM). Photovoltaic devices were prepared with these polymers under different polymer-aggregate conditions. Polymer aggregation induced by thermal annealing increases the short circuit current but provides no advantage in the overall power conversion efficiency because of a decrease in the open circuit voltage. The device fabricated from a pre-aggregated polymer suspension, acquired from ultrasonic agitation of a conjugated polymer gel, showed enhanced performance because of better phase separation and reduced recombination between polymer/PCBM.

  7. Effect of Thai medicinal plant extracts on cell aggregation of Escherichia coli O157: H7.

    Directory of Open Access Journals (Sweden)

    Limsuwan, S.

    2005-08-01

    Full Text Available Medicinal plants have been used for treating diarrhoea but the interference mechanisms are not clearly understood. One possible hypothesis is that of an effect on cell surface hydrophobicity of microbial cells. In this study, we examined cell aggregation affected by crude extracts of Thai medicinal plants on cell surface hydrophobicity of Escherichia coli strains by salt aggregation test. Correlation between minimal inhibitory concentration and cell aggregation was performed. Aqueous and ethanolic extracts of 8 medicinal plants including Acacia catechu, Holarrhena antidysenterica, Peltophorum pterocarpum, Piper sarmentosum, Psidium guajava, Punica granatum, Quercus infectoria, and Tamarindus indica were tested with E. coli O157: H7 and other E. coli strains isolated from human, porcine, and foods. Aqueous extracts of Peltophorum pterocarpum, Psidium guajava, and Punica granatum were highly effective against E. coli O157: H7 with the MIC values of 0.09 to 0.39, 0.19 to 0.78, and 0.09 to 1.56 mg/ml, respectively. Ethanolic extract of Quercus infectoria and Punica granatum demonstrated good MIC values of 0.09 to 0.78, and 0.19 to 0.78 mg/ml, respectively. It was established that aqueous extracts of Punica granatum and Piper sarmentosum at high concentration (25 mg/ml enhanced cell aggregation of almost all E. coli strains while aqueous and ethanolic extracts ofQuercus infectoria enhanced cell aggregation of some E. coli strains. Correlation between minimal inhibitory concentration and cell aggregation was not found in this study.

  8. Transmethylation inhibitors decrease chemotactic sensitivity and delay cell aggregation in Dictyostelium discoideum

    NARCIS (Netherlands)

    van Waarde, A; van Haastert, P J

    1984-01-01

    In Dictyostelium discoideum, extracellular cyclic AMP (cAMP) induces chemotaxis and cell aggregation. Suspensions of cAMP-sensitive cells respond to a cAMP pulse with a rapid, transient increase of protein carboxyl methylation. The transmethylation inhibitors cycloleucine, L-homocysteine thiolactone

  9. Phytoplankton aggregate formation: observations of patterns and mechanisms of cell sticking and the significance of exopolymeric material

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Hansen, Jorgen L. S.

    1993-01-01

    are sticky in themselves, and coagulation depends on cell-cell sticking and does not involve mucus. Aggregates are composed solely of cells. Cells of the diatom Chaetoceros affinis, on the other hand, are not in themselves sticky. Transparent exopolymeric particles (TEP), produced by the diatom, cause...... the cells to aggregate and coagulation depends on TEP-cell rather than cell-cell sticking. Aggregates are formed of a mixture of mucus and cells. We found several species of diatoms and one flagellate species to produce copious amounts of TEP. TEP from some species (e.g. Coscinodiscus sp.) is sticky and may...

  10. Mechanisms of xenogeneic baboon platelet aggregation and phagocytosis by porcine liver sinusoidal endothelial cells.

    Directory of Open Access Journals (Sweden)

    Qiang Peng

    Full Text Available BACKGROUND: Baboons receiving xenogeneic livers from wild type and transgenic pigs survive less than 10 days. One of the major issues is the early development of profound thrombocytopenia that results in fatal hemorrhage. Histological examination of xenotransplanted livers has shown baboon platelet activation, phagocytosis and sequestration within the sinusoids. In order to study the mechanisms of platelet consumption in liver xenotransplantation, we have developed an in vitro system to examine the interaction between pig endothelial cells with baboon platelets and to thereby identify molecular mechanisms and therapies. METHODS: Fresh pig hepatocytes, liver sinusoidal and aortic endothelial cells were isolated by collagenase digestion of livers and processing of aortae from GTKO and Gal+ MGH-miniature swine. These primary cell cultures were then tested for the differential ability to induce baboon or pig platelet aggregation. Phagocytosis was evaluated by direct observation of CFSE labeled-platelets, which are incubated with endothelial cells under confocal light microscopy. Aurintricarboxylic acid (GpIb antagonist blocking interactions with von Willebrand factor/vWF, eptifibatide (Gp IIb/IIIa antagonist, and anti-Mac-1 Ab (anti-α(Mβ(2 integrin Ab were tested for the ability to inhibit phagocytosis. RESULTS: None of the pig cells induced aggregation or phagocytosis of porcine platelets. However, pig hepatocytes, liver sinusoidal and aortic endothelial cells (GTKO and Gal+ all induced moderate aggregation of baboon platelets. Importantly, pig liver sinusoidal endothelial cells efficiently phagocytosed baboon platelets, while pig aortic endothelial cells and hepatocytes had minimal effects on platelet numbers. Anti-MAC-1 Ab, aurintricarboxylic acid or eptifibatide, significantly decreased baboon platelet phagocytosis by pig liver endothelial cells (P<0.01. CONCLUSIONS: Although pig hepatocytes and aortic endothelial cells directly caused

  11. Quantification of the aggregation of magnetic nanoparticles with different polymeric coatings in cell culture medium

    Energy Technology Data Exchange (ETDEWEB)

    Eberbeck, D; Zirpel, P; Trahms, L [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany); Kettering, M; Hilger, I [Institute of Diagnostic and Interventional Radiology, University Hospital Jena, Erlanger Allee 101, 07747 Jena (Germany); Bergemann, C, E-mail: dietmar.eberbeck@ptb.d [Chemicell GmbH, Eresburgstrasse 22-23, 12103 Berlin (Germany)

    2010-10-13

    The knowledge of the physico-chemical characteristics of magnetic nanoparticles (MNPs) is essential to enhance the efficacy of MNP-based therapeutic treatments (e.g. magnetic heating, magnetic drug targeting). According to the literature, the MNP uptake by cells may depend on the coating of MNPs, the surrounding medium as well as on the aggregation behaviour of the MNPs. Therefore, in this study, the aggregation behaviour of MNPs in various media was investigated. MNPs with different coatings were suspended in cell culture medium (CCM) containing fetal calf serum (FCS) and the distribution of the hydrodynamic sizes was measured by magnetorelaxometry (MRX). FCS as well as bovine serum albumin (BSA) buffer (phosphate buffered saline with 0.1% bovine serum albumin) may induce MNP aggregation. Its strength depends crucially on the type of coating. The degree of aggregation in CCM depends on its FCS content showing a clear, local maximum at FCS concentrations, where the IgG concentration (part of FCS) is of the order of the MNP number concentration. Thus, we attribute the observed aggregation behaviour to the mechanism of agglutination of MNPs by serum compartments as for example IgG. No aggregation was induced for MNPs coated with dextran, polyarabic acid or sodium phosphate, respectively, which were colloidally stable in CCM.

  12. Submicrometer-scale ZnO Composite Aggregate Arrays Photoanodes for Dye-sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    Wei Jia; Suihu Dang; Hairui Liu; Zhuxia Zhang; Tianbao Li; Xuguang Liu; Bingshe Xu

    2013-01-01

    Submicrometer-scale ZnO composite aggregate arrays of nanorods and nanoparticles were prepared by simple wet-chemical route and studied as dye-sensitized solar cells (DSSCs) photoanodes.The ZnO composite aggregate arrays significantly improved the efficiency of DSSCs due to their relatively high surface area,fast electron transport,and enhanced light-scattering capability.A short current density (Jsc) of 11.7 mA/cm2 and an overall solar-to-electric energy conversion efficiency (η) of 3.17% were achieved for the ZnO composite aggregate DSSCs,which were much higher than those obtained for the monodisperse aggregate DSSCs (Jsc=6.9mA/cm2,η=1.51 %) and ZnO nanorod array DSSCs (Jsc =4.2 mA/cm2,η=0.61%).

  13. In-cell aggregation of a polyglutamine-containing chimera is a multistep process initiated by the flanking sequence.

    Science.gov (United States)

    Ignatova, Zoya; Thakur, Ashwani K; Wetzel, Ronald; Gierasch, Lila M

    2007-12-14

    Toxicity in amyloid diseases is intimately linked to the nature of aggregates, with early oligomeric species believed to be more cytotoxic than later fibrillar aggregates. Yet mechanistic understanding of how aggregating species evolve with time is currently lacking. We have explored the aggregation process of a chimera composed of a globular protein (cellular retinoic acid-binding protein, CRABP) and huntingtin exon 1 with polyglutamine tracts either above (Q53) or below (Q20) the pathological threshold using Escherichia coli cells as a model intracellular environment. Previously we showed that fusion of the huntingtin exon 1 sequence with >40Q led to structural perturbation and decreased stability of CRABP (Ignatova, Z., and Gierasch, L. M. (2006) J. Biol. Chem. 281, 12959-12967). Here we report that the Q53 chimera aggregates in cells via a multistep process: early stage aggregates are spherical and detergent-soluble, characteristics of prefibrillar aggregates, and appear to be dominated structurally by CRABP, in that they can promote aggregation of a CRABP variant but not oligoglutamine aggregation, and the CRABP domain is relatively sequestered based on its protection from proteolysis. Late stage aggregates appear to be dominated by polyGln; they are fibrillar, detergent-resistant, capable of seeding aggregation of oligoglutamine but not the CRABP variant, and show relative protection of the polyglutamine-exon1 domain from proteolysis. These results point to an evolution of the dominant sequences in intracellular aggregates and may provide molecular insight into origins of toxic prefibrillar aggregates.

  14. Analysis of red blood cell aggregation in cardio-pulmonary bypass (CPB) surgery.

    Science.gov (United States)

    Graaff, R; Gu, Y J; Boonstra, P W; van Oeveren, W; Rakhorst, G

    2004-06-01

    Not much is known about red cell aggregation during cardio-pulmonary bypass surgery (CPB). Blood samples from 19 patients undergoing CPB were anticoagulated with EDTA. Hematocrit was adjusted to 40%. A red blood cell aggregometer (LORCA) measured changes in light reflection from each blood sample after cessation of the rotation, and calculated an aggregation index (AI). Reflection measurements were stored. Because LORCA software failed for 87 of 171 samples, we developed new software, and applied it to the stored reflection measurements. This software failed only in 7 out of 171 cases and showed that all LORCA failures occurred for AI CPB and recovered to 37.1 +/- 13.5 at day 1. It is concluded that the new software can be used to study decreased red cell aggregation during CPB.

  15. A Voronoi Interface approach to cell aggregate electropermeabilization

    Science.gov (United States)

    Guittet, Arthur; Poignard, Clair; Gibou, Frederic

    2017-03-01

    We present a Voronoi Interface approach to the study of cell electropermeabilization. We consider the nonlinear electropermeabilization model of Poignard et al. [20], which takes into account the jump in the voltage potential across cells' membrane. The jump condition is imposed in a sharp manner, using the Voronoi Interface Method of Guittet et al. [14], while adaptive Quad/Oc-tree grids are employed to automatically refine near the cells boundary for increased accuracy. Numerical results are provided to illustrate the accuracy of the methods. We also carry out simulations in three spatial dimensions to investigate the influence of shadowing and of the cells shape on the degree of permeabilization.

  16. Moving Walkways, Escalators, and Elevators

    CERN Document Server

    Cardinal, J; Hurtado, F; Langerman, S; Palop, B

    2007-01-01

    We study a simple geometric model of transportation facility that consists of two points between which the travel speed is high. This elementary definition can model shuttle services, tunnels, bridges, teleportation devices, escalators or moving walkways. The travel time between a pair of points is defined as a time distance, in such a way that a customer uses the transportation facility only if it is helpful. We give algorithms for finding the optimal location of such a transportation facility, where optimality is defined with respect to the maximum travel time between two points in a given set.

  17. CAG Expansions Are Genetically Stable and Form Nontoxic Aggregates in Cells Lacking Endogenous Polyglutamine Proteins

    Directory of Open Access Journals (Sweden)

    Ashley A. Zurawel

    2016-09-01

    Full Text Available Proteins containing polyglutamine (polyQ regions are found in almost all eukaryotes, albeit with various frequencies. In humans, proteins such as huntingtin (Htt with abnormally expanded polyQ regions cause neurodegenerative diseases such as Huntington’s disease (HD. To study how the presence of endogenous polyQ aggregation modulates polyQ aggregation and toxicity, we expressed polyQ expanded Htt fragments (polyQ Htt in Schizosaccharomyces pombe. In stark contrast to other unicellular fungi, such as Saccharomyces cerevisiae, S. pombe is uniquely devoid of proteins with more than 10 Q repeats. We found that polyQ Htt forms aggregates within S. pombe cells only with exceedingly long polyQ expansions. Surprisingly, despite the presence of polyQ Htt aggregates in both the cytoplasm and nucleus, no significant growth defect was observed in S. pombe cells. Further, PCR analysis showed that the repetitive polyQ-encoding DNA region remained constant following transformation and after multiple divisions in S. pombe, in contrast to the genetic instability of polyQ DNA sequences in other organisms. These results demonstrate that cells with a low content of polyQ or other aggregation-prone proteins can show a striking resilience with respect to polyQ toxicity and that genetic instability of repetitive DNA sequences may have played an important role in the evolutionary emergence and exclusion of polyQ expansion proteins in different organisms.

  18. Escalation of commitment with transparent future outcomes.

    Science.gov (United States)

    Karlsson, Niklas; Gärling, Tommy; Bonini, Nicolao

    2005-01-01

    A frequent case of irrational decision making is the tendency to escalate commitment to a chosen course of action after unsuccessful prior investments of money, effort, or time (sunk costs). In previous research it is argued that escalation does not occur when future outcomes and alternative investments are transparent. Inconsistent with this argument, in an experiment in which undergraduates were presented fictitious investment problems with sunk costs, escalation was demonstrated when full information was given about investment alternatives and estimates of future returns. Thus, it is indicated that people may escalate despite knowing that it will not make them economically better off. A more comprehensive understanding of escalation requires disentangling people's noneconomic reasons for escalation.

  19. Photoacoustic ultrasound spectroscopy for assessing red blood cell aggregation and oxygenation

    Science.gov (United States)

    Hysi, Eno; Saha, Ratan K.; Kolios, Michael C.

    2012-12-01

    Red blood cell (RBC) aggregation and oxygenation are important markers for a variety of blood disorders. No current technique is capable of simultaneously measuring aggregation/oxygenation levels noninvasively. We propose using photoacoustic ultrasound spectroscopy (PAUS) for assessing both phenomena. This technique relies on frequency-domain analysis of the PA signals by extracting parameters such as the ultrasound spectral slope and the midband fit. To investigate the effect of hematocrit, aggregation, and oxygenation levels on PAUS parameters, a Monte Carlo-based theoretical model and an experimental protocol using porcine RBCs were developed. The samples were illuminated at 750 and 1064 nm and changes in the PAUS parameters were compared to the oxygen-dependent optical absorption coefficients to assess the oxygenation level. Good agreement between the theoretical and experimental spectral parameters was obtained for the spectral slope of the nonaggregated spectra (˜0.3 dB/MHz). The experimental midband fit increased by ˜5 dB for the largest aggregate size. Based on the analysis of the PA signals, the oxygen saturation level of the most aggregated sample was >20% greater than the nonaggregated sample. The results provide a framework for using PA signals' spectroscopic parameters for monitoring the aggregation and oxygenation levels of RBCs.

  20. Measurement of interaction forces between red blood cells in aggregates by optical tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Maklygin, A Yu; Priezzhev, A V; Karmenian, A; Nikitin, Sergei Yu; Obolenskii, I S; Lugovtsov, Andrei E; Kisun Li

    2012-06-30

    We have fabricated double-beam optical tweezers and demonstrated the possibility of their use for measuring the interaction forces between red blood cells (erythrocytes). It has been established experimentally that prolonged trapping of red blood cells in a tightly focused laser beam does not cause any visible changes in their shape or size. We have measured the interaction between red blood cells in the aggregate, deformed by optical tweezers.

  1. Numerical simulations of deformation and aggregation of red blood cells in shear flow.

    Science.gov (United States)

    Low, Hong-Tong; Ju, M; Sui, Y; Nazir, T; Namgung, B; Kim, Sangho

    2013-01-01

    This article reviews numerical simulations of red blood cells (RBCs) mainly using the lattice Boltzmann method (LBM), focusing on the 2-dimensional deformation and aggregation of the cells in simple shear flow. We outline the incorporation of the immersed boundary method into the LBM, in which the membrane forces are obtained from the membrane model. The RBCs are simulated as a single biconcave capsule and as a doublet of biconcave capsules. The transition from swinging to tumbling motions of the RBCs, as induced by reducing the shear rate or increasing the membrane bending stiffness, is discussed. Also discussed is the aggregation tendency of the doublet of RBCs, for which homogenous deformability maintained RBC aggregation, whereas an increased deformability difference resulted in RBC dissociation.

  2. The Evolution of Aggregative Multicellularity and Cell-Cell Communication in the Dictyostelia.

    Science.gov (United States)

    Du, Qingyou; Kawabe, Yoshinori; Schilde, Christina; Chen, Zhi-Hui; Schaap, Pauline

    2015-11-20

    Aggregative multicellularity, resulting in formation of a spore-bearing fruiting body, evolved at least six times independently amongst both eukaryotes and prokaryotes. Amongst eukaryotes, this form of multicellularity is mainly studied in the social amoeba Dictyostelium discoideum. In this review, we summarise trends in the evolution of cell-type specialisation and behavioural complexity in the four major groups of Dictyostelia. We describe the cell-cell communication systems that control the developmental programme of D. discoideum, highlighting the central role of cAMP in the regulation of cell movement and cell differentiation. Comparative genomic studies showed that the proteins involved in cAMP signalling are deeply conserved across Dictyostelia and their unicellular amoebozoan ancestors. Comparative functional analysis revealed that cAMP signalling in D. discoideum originated from a second messenger role in amoebozoan encystation. We highlight some molecular changes in cAMP signalling genes that were responsible for the novel roles of cAMP in multicellular development.

  3. The cell aggregating propensity of probiotic actinobacterial isolates: isolation and characterization of the aggregation inducing peptide pheromone.

    Science.gov (United States)

    Muthu Selvam, Ramu; Vinothini, Gopal; Palliyarai Thaiyammal, Sethuramalingam; Latha, Selvanathan; Chinnathambi, Arunachalam; Dhanasekaran, Dharumadurai; Padmanabhan, Parasuraman; Ali Alharbi, Sulaiman; Archunan, Govindaraju

    2016-01-01

    The auto-aggregating ability of a probiotic is a prerequisite for colonization and protection of the gastrointestinal tract, whereas co-aggregation provides a close interaction with pathogenic bacteria. Peptide pheromone mediated signaling has been studied in several systems. However, it has not yet been explored in prokaryotes, especially actinobacteria. Hence, in the present study, the diffusible aggregation promoting factor was purified from the culture supernatant of a potent actinobacterial probiont and characterized using 20 different actinobacterial cultures isolated from the gut region of chicken and goat. The results showed that the pheromone-like compound induces the aggregation propensity of treated isolates. The factor was found to be a heat stable, acidic pH resistant, low molecular weight peptide which enhances the biofilm forming ability of other actinobacterial isolates. The aggregation promoting factor represents a bacterial sex factor (pheromone) and its characterization confirms its usage in the probiotic formulation.

  4. Bacillus thuringiensis Cyt2Aa2 toxin disrupts cell membranes by forming large protein aggregates

    Science.gov (United States)

    Tharad, Sudarat; Toca-Herrera, José L.; Promdonkoy, Boonhiang; Krittanai, Chartchai

    2016-01-01

    Bacillus thuringiensis (Bt) Cyt2Aa2 showed toxicity against Dipteran insect larvae and in vitro lysis activity on several cells. It has potential applications in the biological control of insect larvae. Although pore-forming and/or detergent-like mechanisms were proposed, the mechanism underlying cytolytic activity remains unclear. Analysis of the haemolytic activity of Cyt2Aa2 with osmotic stabilizers revealed partial toxin inhibition, suggesting a distinctive mechanism from the putative pore formation model. Membrane permeability was studied using fluorescent dye entrapped in large unilamellar vesicles (LUVs) at various protein/lipid molar ratios. Binding of Cyt2Aa2 monomer to the lipid membrane did not disturb membrane integrity until the critical protein/lipid molar ratio was reached, when Cyt2Aa2 complexes and cytolytic activity were detected. The complexes are large aggregates that appeared as a ladder when separated by agarose gel electrophoresis. Interaction of Cyt2Aa2 with Aedes albopictus cells was investigated by confocal microscopy and total internal reflection fluorescent microscopy (TIRF). The results showed that Cyt2Aa2 binds on the cell membrane at an early stage without cell membrane disruption. Protein aggregation on the cell membrane was detected later which coincided with cell swelling. Cyt2Aa2 aggregations on supported lipid bilayers (SLBs) were visualized by AFM. The AFM topographic images revealed Cyt2Aa2 aggregates on the lipid bilayer at low protein concentration and subsequently disrupts the lipid bilayer by forming a lesion as the protein concentration increased. These results supported the mechanism whereby Cyt2Aa2 binds and aggregates on the lipid membrane leading to the formation of non-specific hole and disruption of the cell membrane. PMID:27612497

  5. Optimization and comparison of two different 3D culture methods to prepare cell aggregates as a bioink for organ printing.

    Science.gov (United States)

    Imani, Rana; Hojjati Emami, Shahriar; Fakhrzadeh, Hossein; Baheiraei, Nafiseh; Sharifi, Ali M

    2012-04-01

    The ultimate goal of tissue engineering is to design and fabricate functional human tissues that are similar to natural cells and are capable of regeneration. Preparation of cell aggregates is one of the important steps in 3D tissue engineering technology, particularly in organ printing. Two simple methods, hanging drop (HD) and conical tube (CT) were utilized to prepare cell aggregates. The size and viability of the aggregates obtained at different initial cell densities and pre-culture duration were compared. The proliferative ability of the cell aggregates and their ability to spread in culture plates were also investigated. In both methods, the optimum average size of the aggregates was less than 500 microm. CT aggregates were smaller than HD aggregates. 5,000 cells per drop HD aggregates showed a marked ability to attach and spread on the culture surface. The proliferative ability reduced when the initial cell density was increased. Comparing these methods, we found that the HD method having better size controlling ability as well as enhanced ability to maintain higher rates of viability, spreading, and proliferation. In conclusion, smaller HD aggregates might be a suitable choice as building blocks for making bioink particles in bioprinting technique.

  6. Normal and system lupus erythematosus red blood cell interactions studied by double trap optical tweezers: direct measurements of aggregation forces

    Science.gov (United States)

    Khokhlova, Maria D.; Lyubin, Eugeny V.; Zhdanov, Alexander G.; Rykova, Sophia Yu.; Sokolova, Irina A.; Fedyanin, Andrey A.

    2012-02-01

    Direct measurements of aggregation forces in piconewton range between two red blood cells in pair rouleau are performed under physiological conditions using double trap optical tweezers. Aggregation and disaggregation properties of healthy and pathologic (system lupus erythematosis) blood samples are analyzed. Strong difference in aggregation speed and behavior is revealed using the offered method which is proposed to be a promising tool for SLE monitoring at single cell level.

  7. Elucidating double aggregation mechanisms in the morphology optimization of diketopyrrolopyrrole-based narrow bandgap polymer solar cells.

    Science.gov (United States)

    Gao, Jing; Chen, Wei; Dou, Letian; Chen, Chun-Chao; Chang, Wei-Hsuan; Liu, Yongsheng; Li, Gang; Yang, Yang

    2014-05-21

    The power conversion efficiency (PCE) of a DPP-based polymer solar cell is significantly improved by using DIO or DCB as processing additives. The discovery that DCB outperforms DIO with a significantly wider solvent mixture operation window suggests different optimization mechanisms. Although both solvent mixture systems involve double aggregation processes, including a similar solution-to-film aggregation, however, two distinct solution-stage aggregations are observed: relatively amorphous polymer aggregates form in the CF-DIO solution, while more crystalline polymer aggregates form in CF-DCB solution.

  8. Photometric measurements of red blood cell aggregation: light transmission versus light reflectance

    NARCIS (Netherlands)

    Baskurt, O.K.; Uyuklu, M.; Hardeman, M.R.; Meiselman, H.J.

    2009-01-01

    Red blood cell (RBC) aggregation is the reversible and regular clumping in the presence of certain macromolecules. This is a clinically important phenomenon, being significantly enhanced in the presence of acute phase reactants (e. g., fibrinogen). Both light reflection (LR) and light transmission (

  9. Characterization at the individual cell level and in whole blood samples of shear stress preventing red blood cells aggregation.

    Science.gov (United States)

    Lee, K; Kinnunen, M; Danilina, A V; Ustinov, V D; Shin, S; Meglinski, I; Priezzhev, A V

    2016-05-03

    The aggregation of red blood cells (RBC) is an intrinsic feature of blood that has a strong impact on its microcirculation. For a number of years it has been attracting a great attention in basic research and clinical studies. Here, we study a relationship between the RBC aggregation parameters measured at the individual cell level and in a whole blood sample. The home made optical tweezers were used to measure the aggregating and disaggregating forces for a pair of interacting RBCs, at the individual cell level, in order to evaluate the corresponding shear stresses. The RheoScan aggregometer was used for the measurements of critical shear stress (CSS) in whole blood samples. The correlation between CSS and the shear stress required to stop an RBC pair from aggregating was found. The shear stress required to disaggregate a pair of RBCs using the double channel optical tweezers appeared to be about 10 times higher than CSS. The correlation between shear stresses required to prevent RBCs from aggregation at the individual cell level and in whole blood samples was estimated and assessed quantitatively. The experimental approach developed has a high potential for advancing hemorheological studies.

  10. Simple and efficient production of mice derived from embryonic stem cells aggregated with tetraploid embryos.

    Science.gov (United States)

    Li, Xiangyun; Yu, Yuansong; Wei, Wei; Yong, Jun; Yang, Jie; You, Jiefang; Xiong, Xiaoran; Qing, Tingting; Deng, Hongkui

    2005-06-01

    Six newly derived hybrid mouse embryonic stem (ES) cell lines and two inbred ES cell lines were tested for their ability to produce completely ES cell-derived mice by aggregation of ES cells with tetraploid embryos. Forty-five ES cell-tetraploid pups were generated from six hybrid ES cell lines and no pups from two inbred ES cell lines. These pups were found to have increased embryonic and placental weights than control mice. Twenty-two pups survived to adulthood and produced normal offsprings, and the other 23 pups died of several reasons including respiratory distress, abdomen ulcer-like symptoms, and foster failure. The 22 adult ES cell-tetraploid mice were completely ES cell-derived as judged by coat color and germline transmission, only two of them was found to have tetraploid component in liver, blood, and lung as analyzed by microsatellite loci. Our data suggested that genetic heterozygosity is a crucial factor for postnatal survival of ES cell-tetraploid mice, and tetraploid embryo aggregation using hybrid ES cells is a simple and efficient procedure for immediate generation of targeted mouse mutants from genetically modified ES cell clones, in contrast to the standard protocol, which involves the production of chimeras and several breeding steps.

  11. Protein carbonylation, protein aggregation and neuronal cell death in a murine model of multiple sclerosis

    Science.gov (United States)

    Dasgupta, Anushka

    Many studies have suggested that oxidative stress plays an important role in the pathophysiology of both multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). Yet, the mechanism by which oxidative stress leads to tissue damage in these disorders is unclear. Recent work from our laboratory has revealed that protein carbonylation, a major oxidative modification caused by severe and/or chronic oxidative stress conditions, is elevated in MS and EAE. Furthermore, protein carbonylation has been shown to alter protein structure leading to misfolding/aggregation. These findings prompted me to hypothesize that carbonylated proteins, formed as a consequence of oxidative stress and/or decreased proteasomal activity, promote protein aggregation to mediate neuronal apoptosis in vitro and in EAE. To test this novel hypothesis, I first characterized protein carbonylation, protein aggregation and apoptosis along the spinal cord during the course of myelin-oligodendrocyte glycoprotein (MOG)35-55 peptide-induced EAE in C57BL/6 mice [Chapter 2]. The results show that carbonylated proteins accumulate throughout the course of the disease, albeit by different mechanisms: increased oxidative stress in acute EAE and decreased proteasomal activity in chronic EAE. I discovered not only that there is a temporal correlation between protein carbonylation and apoptosis but also that carbonyl levels are significantly higher in apoptotic cells. A high number of juxta-nuclear and cytoplasmic protein aggregates containing the majority of the oxidized proteins are also present during the course of EAE, which seems to be due to reduced autophagy. In chapter 3, I show that when gluthathione levels are reduced to those in EAE spinal cord, both neuron-like PC12 (nPC12) cells and primary neuronal cultures accumulate carbonylated proteins and undergo cell death (both by necrosis and apoptosis). Immunocytochemical and biochemical studies also revealed a temporal

  12. Cell Surface Binding and Internalization of Aβ Modulated by Degree of Aggregation

    Directory of Open Access Journals (Sweden)

    David A. Bateman

    2011-01-01

    Full Text Available The amyloid peptides, Aβ40 and Aβ42, are generated through endoproteolytic cleavage of the amyloid precursor protein. Here we have developed a model to investigate the interaction of living cells with various forms of aggregated Aβ40/42. After incubation at endosomal pH 6, we observed a variety of Aβ conformations after 3 (Aβ3, 24 (Aβ24, and 90 hours (Aβ90. Both Aβ4224 and Aβ4024 were observed to rapidly bind and internalize into differentiated PC12 cells, leading to accumulation in the lysosome. In contrast, Aβ40/4290 were both found to only weakly associate with cells, but were observed as the most aggregated using dynamic light scattering and thioflavin-T. Internalization of Aβ40/4224 was inhibited with treatment of monodansylcadaverine, an endocytosis inhibitor. These studies indicate that the ability of Aβ40/42 to bind and internalize into living cells increases with degree of aggregation until it reaches a maximum beyond which its ability to interact with cells diminishes drastically.

  13. Quality of Life (QOL) Analysis of a Randomized Radiation Dose Escalation Non-Small Cell Lung Cancer (NSCLC) Study: Radiation Therapy Oncology Group (RTOG) Trial 0617

    Science.gov (United States)

    Movsas, Benjamin; Hu, Chen; Sloan, Jeffrey; Bradley, Jeffrey; Komaki, Ritsuko; Masters, Gregory; Kavadi, Vivek; Narayan, Samir; Michalski, Jeff; Johnson, Douglas W.; Koprowski, Christopher; Curran, Walter J.; Garces, Yolanda I.; Gaur, Rakesh; Wynn, Raymond B.; Schallenkamp, John; Gelblum, Daphna Y.; MacRae, Robert M; Paulus, Rebecca; Choy, Hak

    2015-01-01

    Importance A recent randomized radiation dose escalation trial in unresectable stage III NSCLC showed a lower survival in the high-dose arm (74Gy vs. 60Gy) with concurrent chemotherapy. Quality of life (QOL), an important secondary endpoint, is presented here. Objective The primary QOL hypothesis predicted a clinically meaningful decline (CMD) in QOL via the Functional Assessment of Cancer Therapy-Lung Cancer Subscale (FACT-LCS) in the high-dose RT-arm at 3 months. Design RTOG 0617 was a randomized phase III study (conducted from Nov 2007 to Nov 2011) in stage III NSCLC using a 2×2 factorial design and stratified by histology, PET staging, performance status and radiation technique (3D-conformal RT [3DCRT] vs. intensity-modulated radiation [IMRT]). Setting 185 institutions in the USA and Canada. Participants Of 424 eligible stage III NSCLC patients randomized, 360 (85%) consented to QOL, of whom 313 (88%) completed baseline QOL assessments. Intervention for Clinical Trials 74Gy vs. 60Gy with concurrent and consolidation carboplatin/paclitaxel +/− cetuximab. Main Outcomes and Measures QOL was collected prospectively via FACT-Trial Outcome Index (FACT-TOI), equaling Physical-Well-Being (PWB) + Functional-Well-Being (FWB) + Lung Cancer Subscale (LCS). Data are presented at baseline & 3 and 12 months via minimal clinically meaningful changes of >=2 points for PWB, FWB or LCS or >=5 points for TOI. Results Patient demographics and baseline QOL scores were comparable between the 74Gy and 60Gy arms. Two-hundred-nineteen (72%) of living patients who completed QOL at baseline did so at 3 months and 137 (57%) of living patients did so at 12 months. Significantly more patients on 74Gy arm had clinically meaningful decline in FACT-LCS at 3 months than on the 60Gy arm (45% vs. 30%, p=0.02). At 12 months, fewer patients who received IMRT (vs 3DCRT) had clinically meaningful decline in FACT-LCS (21% vs 46%, p=0.003). Baseline FACT-TOI was associated with overall survival in

  14. Bioengineering of injectable encapsulated aggregates of pluripotent stem cells for therapy of myocardial infarction

    Science.gov (United States)

    Zhao, Shuting; Xu, Zhaobin; Wang, Hai; Reese, Benjamin E.; Gushchina, Liubov V.; Jiang, Meng; Agarwal, Pranay; Xu, Jiangsheng; Zhang, Mingjun; Shen, Rulong; Liu, Zhenguo; Weisleder, Noah; He, Xiaoming

    2016-10-01

    It is difficult to achieve minimally invasive injectable cell delivery while maintaining high cell retention and animal survival for in vivo stem cell therapy of myocardial infarction. Here we show that pluripotent stem cell aggregates pre-differentiated into the early cardiac lineage and encapsulated in a biocompatible and biodegradable micromatrix, are suitable for injectable delivery. This method significantly improves the survival of the injected cells by more than six-fold compared with the conventional practice of injecting single cells, and effectively prevents teratoma formation. Moreover, this method significantly enhances cardiac function and survival of animals after myocardial infarction, as a result of a localized immunosuppression effect of the micromatrix and the in situ cardiac regeneration by the injected cells.

  15. Passage number affects the pluripotency of mouse embryonic stem cells as judged by tetraploid embryo aggregation.

    Science.gov (United States)

    Li, Xiang-Yun; Jia, Qing; Di, Ke-Qian; Gao, Shu-Min; Wen, Xiao-Hui; Zhou, Rong-Yan; Wei, Wei; Wang, Li-Ze

    2007-03-01

    The aim of this study was to determine whether the number of passages affected the developmental pluripotency of embryonic stem (ES) cells as measured by the attainment of adult fertile mice derived from embryonic stem (ES) cell/tetraploid embryo complementation. Thirty-six newborns were produced by the aggregation of tetraploid embryos and hybrid ES cells after various numbers of passages. These newborns were entirely derived from ES cells as judged by microsatellite DNA, coat-color phenotype, and germline transmission. Although 15 survived to adulthood, 17 died of respiratory failure, and four were eaten by their foster mother. From the 15 mice that reached adulthood and that could reproduce, none arose from ES cells at passage level 15 or more. All 15 arose from cells at passages 3-11. Our results demonstrate that the number of passages affects the developmental pluripotency of ES cells.

  16. Generation of chimeras by aggregation of embryonic stem cells with diploid or tetraploid mouse embryos.

    Science.gov (United States)

    Artus, Jérôme; Hadjantonakis, Anna-Katerina

    2011-01-01

    From the hybrid creatures of the Greek and Egyptian mythologies, the concept of the chimera has evolved and, in modern day biology, refers to an organism comprises of at least two populations of genetically distinct cells. Mouse chimeras have proven an invaluable tool for the generation of genetically modified strains. In addition, chimeras have been extensively used in developmental biology as a powerful tool to analyze the phenotype of specific mutations, to attribute function to gene products and to address the question of cell autonomy versus noncell autonomy of gene function. This chapter describes a simple and economical technique used to generate mouse chimeras by embryo aggregation. Multiple aggregation combinations are described each of which can be tailored to answer particular biological questions.

  17. Uplink Inter-Site Carrier Aggregation Between Macro and Small Cells in Heterogeneous Networks

    DEFF Research Database (Denmark)

    Wang, Hua; Rosa, Claudio; Pedersen, Klaus I.

    2014-01-01

    With uplink inter-site carrier aggregation (CA), it is possible to configure a user equipment (UE) to transmit on multiple layers (macro and small cells) simultaneously, each of which may exhibit different radio channel characteristics. This introduces new challenging issues such as how to config......With uplink inter-site carrier aggregation (CA), it is possible to configure a user equipment (UE) to transmit on multiple layers (macro and small cells) simultaneously, each of which may exhibit different radio channel characteristics. This introduces new challenging issues such as how...... deciding whether UEs should be configured with uplink inter-site CA or not. Simulation results show that with proper configuration of UEs to operate with uplink inter-site CA, good user throughput gain compared to the case without inter-site CA can be achieved at low load due to larger bandwidth...

  18. Neutrophil Cathepsin G, but Not Elastase, Induces Aggregation of MCF-7 Mammary Carcinoma Cells by a Protease Activity-Dependent Cell-Oriented Mechanism

    Directory of Open Access Journals (Sweden)

    Satoru Yui

    2014-01-01

    Full Text Available We previously found that a neutrophil serine protease, cathepsin G, weakens adherence to culture substrates and induces E-cadherin-dependent aggregation of MCF-7 human breast cancer cells through its protease activity. In this study, we examined whether aggregation is caused by degradation of adhesion molecules on the culture substrates or through an unidentified mechanism. We compared the effect of treatment with cathepsin G and other proteases, including neutrophil elastase against fibronectin- (FN- coated substrates. Cathepsin G and elastase potently degraded FN on the substrates and induced aggregation of MCF-7 cells that had been subsequently seeded onto the substrate. However, substrate-bound cathepsin G and elastase may have caused cell aggregation. After inhibiting the proteases on the culture substrates using the irreversible inhibitor phenylmethylsulfonyl fluoride (PMSF, we examined whether aggregation of MCF-7 cells was suppressed. PMSF attenuated cell aggregation on cathepsin G-treated substrates, but the effect was weak in cells pretreated with high concentrations of cathepsin G. In contrast, PMSF did not suppress cell aggregation on elastase-treated FN. Moreover, cathepsin G, but not elastase, induced aggregation on poly-L-lysine substrates which are not decomposed by these enzymes, and the action of cathepsin G was nearly completely attenuated by PMSF. These results suggest that cathepsin G induces MCF-7 aggregation through a cell-oriented mechanism.

  19. Modulation of invasive phenotype by interstitial pressure-driven convection in aggregates of human breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Joe Tien

    Full Text Available This paper reports the effect of elevated pressure on the invasive phenotype of patterned three-dimensional (3D aggregates of MDA-MB-231 human breast cancer cells. We found that the directionality of the interstitial pressure profile altered the frequency of invasion by cells located at the surface of an aggregate. In particular, application of pressure at one end of an aggregate suppressed invasion at the opposite end. Experimental alteration of the configuration of cell aggregates and computational modeling of the resulting flow and solute concentration profiles revealed that elevated pressure inhibited invasion by altering the chemical composition of the interstitial fluid near the surface of the aggregate. Our data reveal a link between hydrostatic pressure, interstitial convection, and invasion.

  20. Modeling multivalent ligand-receptor interactions with steric constraints on configurations of cell surface receptor aggregates

    Energy Technology Data Exchange (ETDEWEB)

    Monine, Michael [Los Alamos National Laboratory; Posner, Richard [TRANSLATION GENOMICS RESAEARCH INSTITUTE; Savage, Paul [BYU; Faeder, James [UNIV OF PITTSBURGH; Hlavacek, William S [UNM

    2008-01-01

    Signal transduction generally involves multivalent protein-protein interactions, which can produce various protein complexes and post-translational modifications. The reaction networks that characterize these interactions tend to be so large as to challenge conventional simulation procedures. To address this challenge, a kinetic Monte Carlo (KMC) method has been developed that can take advantage of a model specification in terms of reaction rules for molecular interactions. A set of rules implicitly defines the reactions that can occur as a result of the interactions represented by the rules. With the rule-based KMC method, explicit generation of the underlying chemical reaction network implied by rules is avoided. Here, we apply and extend this method to characterize the interactions of a trivalent ligand with a bivalent cell-surface receptor. This system is also studied experimentally. We consider the following kinetic models: an equivalent-site model, an extension of this model, which takes into account steric constraints on the configurations of receptor aggregates, and finally, a model that accounts for cyclic receptor aggregates. Simulation results for the equivalent-site model are consistent with an equilibrium continuum model. Using these models, we investigate the effects of steric constraints and the formation of cyclic aggregates on the kinetics and equilibria of small and large aggregate formation and the percolation phase transition that occurs in this system.

  1. Solvents induced ZnO nanoparticles aggregation associated with their interfacial effect on organic solar cells.

    Science.gov (United States)

    Li, Pandeng; Jiu, Tonggang; Tang, Gang; Wang, Guojie; Li, Jun; Li, Xiaofang; Fang, Junfeng

    2014-10-22

    ZnO nanofilm as a cathode buffer layer has surface defects due to the aggregations of ZnO nanoparticles, leading to poor device performance of organic solar cells. In this paper, we report the ZnO nanoparticles aggregations in solution can be controlled by adjusting the solvents ratios (chloroform vs methanol). These aggregations could influence the morphology of ZnO film. Therefore, compact and homogeneous ZnO film can be obtained to help achieve a preferable power conversion efficiency of 8.54% in inverted organic solar cells. This improvement is attributed to the decreased leakage current and the increased electron-collecting efficiency as well as the improved interface contact with the active layer. In addition, we find the enhanced maximum exciton generation rate and exciton dissociation probability lead to the improvement of device performance due to the preferable ZnO dispersion. Compared to other methods of ZnO nanofilm fabrication, it is the more convenient, moderate, and effective to get a preferable ZnO buffer layer for high-efficiency organic solar cells.

  2. Regulator of G protein signaling 20 enhances cancer cell aggregation, migration, invasion and adhesion.

    Science.gov (United States)

    Yang, Lei; Lee, Maggie M K; Leung, Manton M H; Wong, Yung H

    2016-11-01

    Several RGS (regulator of G protein signaling) proteins are known to be upregulated in a variety of tumors but their roles in modulating tumorigenesis remain undefined. Since the expression of RGS20 is elevated in metastatic melanoma and breast tumors, we examined the effects of RGS20 overexpression and knockdown on the cell mobility and adhesive properties of different human cancer cell lines, including cervical cancer HeLa, breast adenocarcinoma MDA-MB-231, and non-small cell lung carcinoma H1299 and A549 cells. Expression of RGS20 enhanced cell aggregation, migration, invasion and adhesion as determined by hanging drop aggregation, wound healing, transwell chamber migration and invasion assays. Conversely, shRNA-mediated knockdown of endogenous RGS20 impaired these responses. In addition, RGS20 elevated the expression of vimentin (a mesenchymal cell marker) but down-regulated the expression of E-cadherin, two indicators commonly associated with metastasis. These results suggest that the expression of RGS20 may promote metastasis of tumor cells.

  3. Optimising cell aggregate expansion in a perfused hollow fibre bioreactor via mathematical modelling.

    KAUST Repository

    Chapman, Lloyd A C

    2014-08-26

    The need for efficient and controlled expansion of cell populations is paramount in tissue engineering. Hollow fibre bioreactors (HFBs) have the potential to meet this need, but only with improved understanding of how operating conditions and cell seeding strategy affect cell proliferation in the bioreactor. This study is designed to assess the effects of two key operating parameters (the flow rate of culture medium into the fibre lumen and the fluid pressure imposed at the lumen outlet), together with the cell seeding distribution, on cell population growth in a single-fibre HFB. This is achieved using mathematical modelling and numerical methods to simulate the growth of cell aggregates along the outer surface of the fibre in response to the local oxygen concentration and fluid shear stress. The oxygen delivery to the cell aggregates and the fluid shear stress increase as the flow rate and pressure imposed at the lumen outlet are increased. Although the increased oxygen delivery promotes growth, the higher fluid shear stress can lead to cell death. For a given cell type and initial aggregate distribution, the operating parameters that give the most rapid overall growth can be identified from simulations. For example, when aggregates of rat cardiomyocytes that can tolerate shear stresses of up to 0:05 Pa are evenly distributed along the fibre, the inlet flow rate and outlet pressure that maximise the overall growth rate are predicted to be in the ranges 2.75 x 10(-5) m(2) s(-1) to 3 x 10(-5) m(2) s(-1) (equivalent to 2.07 ml min(-1) to 2.26 ml min(-1)) and 1.077 x 10(5) Pa to 1.083 x 10(5) Pa (or 15.6 psi to 15.7 psi) respectively. The combined effects of the seeding distribution and flow on the growth are also investigated and the optimal conditions for growth found to depend on the shear tolerance and oxygen demands of the cells.

  4. Escalate shamefully, de-escalate angrily or gratefully: the influence of discrete emotions on escalation of commitment.

    Science.gov (United States)

    Dang, Junhua; Xiao, Shanshan; Liljedahl, Sophie

    2014-08-01

    Decision makers often tend to escalate their commitment when faced with a dilemma of whether to continue a losing course of action. Researchers recently began to investigate the influence of discrete emotions on this decision tendency. However, this work has mainly focused on negative emotions and rarely considered positive emotions, to say nothing of comparing the effects of both of them simultaneously. The current study addresses this need by presenting the results of three experiments that examined the effects of four emotions of both positive and negative valences in escalation situations. Experiment 1 investigated the relationships of three trait emotions (hope, shame, and anger) and escalation of commitment. Experiments 2 and 3 examined the effects of three induced emotions (anger, shame, and gratitude) on escalation of commitment in a student sample and an employee sample, respectively. The results revealed that the effects of discrete emotions in escalation situations are mainly due to their associated differences on the appraisal dimension of responsibility that is related to escalation situations rather than their valence. The theoretical and practical implications are discussed.

  5. Cell surface alterations during blood-storage characterized by artificial aggregation of washed red blood cells.

    Science.gov (United States)

    Hessel, E; Lerche, D

    1985-01-01

    Aggregation measurement of washed human erythrocytes (RBC) were carried out in a NaCl-PBS solution under laminar shear conditions. Artificial aggregation of fresh and stored erythrocytes was caused by decreased pH and reduced ionic strength and characterized by collision efficiency alpha. Generally, the collision efficiency alpha of stored erythrocytes rises with the increased storage time. Such an aggregation technique might be useful to detect and quantify changes of the membrane and/or the surface structure due to aging and/or storage.

  6. Finite-size corrections to scaling behavior in sorted cell aggregates.

    Science.gov (United States)

    Klopper, A V; Krens, G; Grill, S W; Heisenberg, C-P

    2010-10-01

    Cell sorting is a widespread phenomenon pivotal to the early development of multicellular organisms. In vitro cell sorting studies have been instrumental in revealing the cellular properties driving this process. However, these studies have as yet been limited to two-dimensional analysis of three-dimensional cell sorting events. Here we describe a method to record the sorting of primary zebrafish ectoderm and mesoderm germ layer progenitor cells in three dimensions over time, and quantitatively analyze their sorting behavior using an order parameter related to heterotypic interface length. We investigate the cell population size dependence of sorted aggregates and find that the germ layer progenitor cells engulfed in the final configuration display a relationship between total interfacial length and system size according to a simple geometrical argument, subject to a finite-size effect.

  7. Enzymatically degradable poly(ethylene glycol) hydrogels for the 3D culture and release of human embryonic stem cell derived pancreatic precursor cell aggregates.

    Science.gov (United States)

    Amer, Luke D; Holtzinger, Audrey; Keller, Gordon; Mahoney, Melissa J; Bryant, Stephanie J

    2015-08-01

    This study aimed to develop a three dimensional culture platform for aggregates of human embryonic stem cell (hESC)-derived pancreatic progenitors that enables long-term culture, maintains aggregate size and morphology, does not adversely affect differentiation and provides a means for aggregate recovery. A platform was developed with poly(ethylene glycol) hydrogels containing collagen type I, for cell-matrix interactions, and peptide crosslinkers, for facile recovery of aggregates. The platform was first demonstrated with RIN-m5F cells, showing encapsulation and subsequent release of single cells and aggregates without adversely affecting viability. Aggregates of hESC-derived pancreatic progenitors with an effective diameter of 82 (15)μm were either encapsulated in hydrogels or cultured in suspension for 28 days. At day 14, aggregate viability was maintained in the hydrogels, but significantly reduced (88%) in suspension culture. However by day 28, viability was reduced under both culture conditions. Aggregate size was maintained in the hydrogels, but in suspension was significantly higher (∼ 2-fold) by day 28. The ability to release aggregates followed by a second enzyme treatment to achieve single cells enabled assessment by flow cytometry. Prior to encapsulation, there were 39% Pdx1(+)/Nkx6.1(+) cells, key endocrine markers required for β-cell maturation. The fraction of doubly positive cells was not affected in hydrogels but was slightly and significantly lower in suspension culture by 28 days. In conclusion, we demonstrate that a MMP-sensitive PEG hydrogel containing collagen type I is a promising platform for hESC-derived pancreatic progenitors that maintains viable aggregates, aggregate size, and progenitor state and offers facile recovery of aggregates.

  8. Aggregates of mutant CFTR fragments in airway epithelial cells of CF lungs: new pathologic observations.

    Science.gov (United States)

    Du, Kai; Karp, Philip H; Ackerley, Cameron; Zabner, Joseph; Keshavjee, Shaf; Cutz, Ernest; Yeger, Herman

    2015-03-01

    Cystic fibrosis (CF) is caused by a mutation in the CF transmembrane conductance regulator (CFTR) gene resulting in a loss of Cl(-) channel function, disrupting ion and fluid homeostasis, leading to severe lung disease with airway obstruction due to mucus plugging and inflammation. The most common CFTR mutation, F508del, occurs in 90% of patients causing the mutant CFTR protein to misfold and trigger an endoplasmic reticulum based recycling response. Despite extensive research into the pathobiology of CF lung disease, little attention has been paid to the cellular changes accounting for the pathogenesis of CF lung disease. Here we report a novel finding of intracellular retention and accumulation of a cleaved fragment of F508del CFTR in concert with autophagic like phagolysosomes in the airway epithelium of patients with F508del CFTR. Aggregates consisting of poly-ubiquitinylated fragments of only the N-terminal domain of F508del CFTR but not the full-length molecule accumulate to appreciable levels. Importantly, these undegraded intracytoplasmic aggregates representing the NT-NBD1 domain of F508del CFTR were found in ciliated, in basal, and in pulmonary neuroendocrine cells. Aggregates were found in both native lung tissues and ex-vivo primary cultures of bronchial epithelial cells from CF donors, but not in normal control lungs. Our findings present a new, heretofore, unrecognized innate CF gene related cell defect and a potential contributing factor to the pathogenesis of CF lung disease. Mutant CFTR intracytoplasmic aggregates could be analogous to the accumulation of misfolded proteins in other degenerative disorders and in pulmonary "conformational protein-associated" diseases. Consequently, potential alterations to the functional integrity of airway epithelium and regenerative capacity may represent a critical new element in the pathogenesis of CF lung disease.

  9. Symmetry breaking, germ layer specification and axial organisation in aggregates of mouse embryonic stem cells.

    Science.gov (United States)

    van den Brink, Susanne C; Baillie-Johnson, Peter; Balayo, Tina; Hadjantonakis, Anna-Katerina; Nowotschin, Sonja; Turner, David A; Martinez Arias, Alfonso

    2014-11-01

    Mouse embryonic stem cells (mESCs) are clonal populations derived from preimplantation mouse embryos that can be propagated in vitro and, when placed into blastocysts, contribute to all tissues of the embryo and integrate into the normal morphogenetic processes, i.e. they are pluripotent. However, although they can be steered to differentiate in vitro into all cell types of the organism, they cannot organise themselves into structures that resemble embryos. When aggregated into embryoid bodies they develop disorganised masses of different cell types with little spatial coherence. An exception to this rule is the emergence of retinas and anterior cortex-like structures under minimal culture conditions. These structures emerge from the cultures without any axial organisation. Here, we report that small aggregates of mESCs, of about 300 cells, self-organise into polarised structures that exhibit collective behaviours reminiscent of those that cells exhibit in early mouse embryos, including symmetry breaking, axial organisation, germ layer specification and cell behaviour, as well as axis elongation. The responses are signal specific and uncouple processes that in the embryo are tightly associated, such as specification of the anteroposterior axis and anterior neural development, or endoderm specification and axial elongation. We discuss the meaning and implications of these observations and the potential uses of these structures which, because of their behaviour, we suggest to call 'gastruloids'.

  10. Prefoldin Protects Neuronal Cells from Polyglutamine Toxicity by Preventing Aggregation Formation*

    Science.gov (United States)

    Tashiro, Erika; Zako, Tamotsu; Muto, Hideki; Itoo, Yoshinori; Sörgjerd, Karin; Terada, Naofumi; Abe, Akira; Miyazawa, Makoto; Kitamura, Akira; Kitaura, Hirotake; Kubota, Hiroshi; Maeda, Mizuo; Momoi, Takashi; Iguchi-Ariga, Sanae M. M.; Kinjo, Masataka; Ariga, Hiroyoshi

    2013-01-01

    Huntington disease is caused by cell death after the expansion of polyglutamine (polyQ) tracts longer than ∼40 repeats encoded by exon 1 of the huntingtin (HTT) gene. Prefoldin is a molecular chaperone composed of six subunits, PFD1–6, and prevents misfolding of newly synthesized nascent polypeptides. In this study, we found that knockdown of PFD2 and PFD5 disrupted prefoldin formation in HTT-expressing cells, resulting in accumulation of aggregates of a pathogenic form of HTT and in induction of cell death. Dead cells, however, did not contain inclusions of HTT, and analysis by a fluorescence correlation spectroscopy indicated that knockdown of PFD2 and PFD5 also increased the size of soluble oligomers of pathogenic HTT in cells. In vitro single molecule observation demonstrated that prefoldin suppressed HTT aggregation at the small oligomer (dimer to tetramer) stage. These results indicate that prefoldin inhibits elongation of large oligomers of pathogenic Htt, thereby inhibiting subsequent inclusion formation, and suggest that soluble oligomers of polyQ-expanded HTT are more toxic than are inclusion to cells. PMID:23720755

  11. Chapter 3: A fluorescent window into protein folding and aggregation in cells.

    Science.gov (United States)

    Ignatova, Zoya; Gierasch, Lila M

    2008-01-01

    Evolutionary selective pressures have tuned the efficiency of the protein-folding reaction in the crowded complex environment in the cell. Nevertheless, the fidelity of folding is imperfect, leading to off-pathway intermolecular interactions that compete with proper folding and to consequent formation of thermodynamically stable aggregates. Such aggregates constitute the histopathological hallmarks of many neurodegenerative pathologies. Yet, most of the approaches to characterize protein folding and/or misfolding are limited to in vitro conditions. Here, we describe a strategy to directly monitor the behavior of a protein in prokaryotic and eukaryotic cells. The method is based on incorporation of structurally non-perturbing, specific binding motifs for a bis-arsenical fluoroscein dye, FlAsH, in sites that result in distinct dye fluorescence signals for the folded and unfolded states of the protein under study. Our approach has been developed using as a case study the predominantly beta-sheet intracellular lipid-binding protein, cellular retinoic acid-binding protein, alone or as a chimera fused to the exon 1-encoded fragment of huntingtin, which harbors a polyglutamine repeat tract. We have designed protocols to label this protein in vivo and to monitor the resulting fluorescence signal, which reports on any misfolding transition and formation of aggregates, yielding quantitatively interpretable data.

  12. Glyceraldehyde 3-phosphate dehydrogenase augments the intercellular transmission and toxicity of polyglutamine aggregates in a cell model of Huntington disease.

    Science.gov (United States)

    Mikhaylova, Elena R; Lazarev, Vladimir F; Nikotina, Alina D; Margulis, Boris A; Guzhova, Irina V

    2016-03-01

    The common feature of Huntington disease is the accumulation of oligomers or aggregates of mutant huntingtin protein (mHTT), which causes the death of a subset of striatal neuronal populations. The cytotoxic species can leave neurons and migrate to other groups of cells penetrating and damaging them in a prion-like manner. We hypothesized that the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH), previously shown to elevate the aggregation of mHTT, is associated with an increased efficiency of intercellular propagation of mHTT. GAPDH, on its own or together with polyglutamine species, was shown to be released into the extracellular milieu mainly from dying cells as assessed by a novel enzyme immunoassay, western blotting, and ultrafiltration. The conditioned medium of cells with growing GAPDH-polyQ aggregates was toxic to naïve cells, whereas depletion of the aggregates from the medium lowered this cytotoxicity. The GAPDH component of the aggregates was found to increase their toxicity by two-fold in comparison with polyQ alone. Furthermore, GAPDH-polyQ complexes were shown to penetrate acceptor cells and to increase the capacity of polyQ to prionize its intracellular homolog containing a repeat of 25 glutamine residues. Finally, inhibitors of intracellular transport showed that polyQ-GAPDH complexes, as well as GAPDH itself, penetrated cells using clathrin-mediated endocytosis. This suggested a pivotal role of the enzyme in the intercellular transmission of Huntington disease pathogenicity. In conclusion, GAPDH occurring in complexes with polyglutamine strengthens the prion-like activity and toxicity of the migrating aggregates. Aggregating polygluatmine tracts were shown to release from the cells over-expressing mutant huntingtin in a complex with glyceraldehyde 3-phosphate dehydrogenase (GAPDH). The enzyme enhances the intracellular transport of aggregates to healthy cells, prionization of normal cellular proteins and finally cell death, thus

  13. Quantitation of soluble aggregates in recombinant monoclonal antibody cell culture by pH-gradient protein A chromatography.

    Science.gov (United States)

    Pan, Hai; Chen, Ken; Pulisic, Matt; Apostol, Izydor; Huang, Gang

    2009-05-15

    Monoclonal antibodies (mAbs) produced from mammalian cell culture may contain significant amounts of dimers and higher order aggregates. Quantitation of soluble aggregates in the cell culture is time-consuming and labor-intensive, usually involving a purification step to remove the impurities that interfere with the subsequent size exclusion chromatography (SEC) analysis. We have developed a novel pH-gradient protein A chromatography for rapid, non-size based separation of the aggregates in mAb cell culture samples. Our results demonstrate that this method has excellent correlation with SEC and can be applied to both human immunoglobulin gamma 1 (IgG1) and IgG2 antibodies. This approach can be useful in the quantitation of soluble aggregates in crude cell culture samples.

  14. Putative porcine embryonic stem cell lines derived from aggregated four-celled cloned embryos produced by oocyte bisection cloning.

    Science.gov (United States)

    Siriboon, Chawalit; Lin, Yu-Hsuan; Kere, Michel; Chen, Chun-Da; Chen, Lih-Ren; Chen, Chien-Hong; Tu, Ching-Fu; Lo, Neng-Wen; Ju, Jyh-Cherng

    2015-01-01

    We attempted to isolate ES cell lines using inner cell masses from high-quality cloned porcine blastocysts. After being seeded onto feeders, embryos had better (P cloned embryos (62.8, 42.6 and 12.8% vs. 76.2, 55.2 and 26.2%, respectively) compared to the non-aggregated group (41.6, 23.4 and 3.9%). Effects of feeder types (STO vs. MEF) and serum sources (FBS vs. KSR) on extraction of cloned embryo-derived porcine ES cells were examined. More (17.1%) ntES cell lines over Passage 3 were generated in the MEF/KSR group. However, ntES cells cultured in KSR-supplemented medium had a low proliferation rate with defective morphology, and eventually underwent differentiation or apoptosis subsequently. Approximately 26.1, 22.7 and 35.7% of primary colonies were formed after plating embryos in DMEM, DMEM/F12 and α-MEM media, respectively. Survival rates of ntES cells cultured in α-MEM, DMEM and DMEM/F12 were 16.7, 4.3 and 6.8%, respectively (P > 0.05). We further examined the beneficial effect of TSA treatment of 3× aggregated cloned embryos on establishment of ntES cell lines. Primary colony numbers and survival rates of ntES cells beyond passage 3 were higher (P cloned embryos produced by embryo aggregation, and optimized the ES cell culture system suitable for establishing and maintaining ntES cell lines in undifferentiated state.

  15. Entamoeba Clone-Recognition Experiments: Morphometrics, Aggregative Behavior, and Cell-Signaling Characterization.

    Science.gov (United States)

    Espinosa, Avelina; Paz-Y-Miño-C, Guillermo; Hackey, Meagan; Rutherford, Scott

    2016-05-01

    Studies on clone- and kin-discrimination in protists have proliferated during the past decade. We report clone-recognition experiments in seven Entamoeba lineages (E. invadens IP-1, E. invadens VK-1:NS, E. terrapinae, E. moshkovskii Laredo, E. moshkovskii Snake, E. histolytica HM-1:IMSS and E. dispar). First, we characterized morphometrically each clone (length, width, and cell-surface area) and documented how they differed statistically from one another (as per single-variable or canonical-discriminant analyses). Second, we demonstrated that amebas themselves could discriminate self (clone) from different (themselves vs. other clones). In mix-cell-line cultures between closely-related (E. invadens IP-1 vs. E. invadens VK-1:NS) or distant-phylogenetic clones (E. terrapinae vs. E. moshkovskii Laredo), amebas consistently aggregated with same-clone members. Third, we identified six putative cell-signals secreted by the amebas (RasGap/Ankyrin, coronin-WD40, actin, protein kinases, heat shock 70, and ubiquitin) and which known functions in Entamoeba spp. included: cell proliferation, cell adhesion, cell movement, and stress-induced encystation. To our knowledge, this is the first multi-clone characterization of Entamoeba spp. morphometrics, aggregative behavior, and cell-signaling secretion in the context of clone-recognition. Protists allow us to study cell-cell recognition from ecological and evolutionary perspectives. Modern protistan lineages can be central to studies about the origins and evolution of multicellularity.

  16. Brain Aggregates: An Effective In Vitro Cell Culture System Modeling Neurodegenerative Diseases.

    Science.gov (United States)

    Ahn, Misol; Kalume, Franck; Pitstick, Rose; Oehler, Abby; Carlson, George; DeArmond, Stephen J

    2016-03-01

    Drug discovery for neurodegenerative diseases is particularly challenging because of the discrepancies in drug effects between in vitro and in vivo studies. These discrepancies occur in part because current cell culture systems used for drug screening have many limitations. First, few cell culture systems accurately model human aging or neurodegenerative diseases. Second, drug efficacy may differ between dividing and stationary cells, the latter resembling nondividing neurons in the CNS. Brain aggregates (BrnAggs) derived from embryonic day 15 gestation mouse embryos may represent neuropathogenic processes in prion disease and reflect in vivo drug efficacy. Here, we report a new method for the production of BrnAggs suitable for drug screening and suggest that BrnAggs can model additional neurological diseases such as tauopathies. We also report a functional assay with BrnAggs by measuring electrophysiological activities. Our data suggest that BrnAggs could serve as an effective in vitro cell culture system for drug discovery for neurodegenerative diseases.

  17. Removal of sialic acid from the surface of human MCF-7 mammary cancer cells abolishes E-cadherin-dependent cell-cell adhesion in an aggregation assay.

    Science.gov (United States)

    Deman, J J; Van Larebeke, N A; Bruyneel, E A; Bracke, M E; Vermeulen, S J; Vennekens, K M; Mareel, M M

    1995-09-01

    MCF-7 human breast cancer cells express E-cadherin and show, at least in some circumstances, E-cadherin-dependent cell-cell adhesion (Bracke et al., 1993). The MCF-7/AZ variant spontaneously displays E-cadherin-dependent fast aggregation; in the MCF-7/6 variant, E-cadherin appeared not to be spontaneously functional in the conditions of the fast aggregation assay, but function could be induced by incubation of the suspended cells in the presence of insulinlike growth factor I (IGF-I) (Bracke et al., 1993). E-cadherin from MCF-7 cells was shown to contain sialic acid. Treatment with neuraminidase was shown to remove this sialic acid, as well as most of the sialic acid present at the cell surface. Applied to MCF-7/AZ, and MCF-7/6 cells, pretreatment with neuraminidase abolished spontaneous as well as IGF-I induced, E-cadherin-dependent fast cell-cell adhesion of cells in suspension, as measured in the fast aggregation assay. Treatment with neuraminidase did not, however, inhibit the possibly different, but equally E-cadherin-mediated, process of cell-cell adhesion of MCF-7 cells on a flat plastic substrate as assessed by determining the percentage of cells remaining isolated (without contact with other cells) 24 h after plating.

  18. Erlotinib dosing-to-rash: A phase II intrapatient dose escalation and pharmacologic study of erlotinib in previously treated advanced non-small cell lung cancer

    NARCIS (Netherlands)

    A. mita (Alain); K. Papadopoulos (K.); M.J.A. de Jonge (Maja); G. Schwartz (G.); J. Verweij (Jaap); A. Ricart (A.); Q.S.C. Chu (Q. S C); A.W. Tolcher (A. W.); L. Wood (Lori); S.W. McCarthy (Stanley); M. Hamilton; K.K. Iwata (Kenneth); B. Wacker; K. de Witte (Karel); E.K. Rowinsky (Eric Keith)

    2011-01-01

    textabstractBackground: To evaluate the anticancer activity of erlotinib in patients with previously treated, advanced non-small cell lung cancer (NSCLC) whose dose is increased to that associated with a maximal level of tolerable skin toxicity (i.e., target rash (TR)); to characterise the pharmacok

  19. Prophylactic G-CSF and antibiotics enable a significant dose-escalation of triplet-chemotherapy in non-small cell lung cancer.

    NARCIS (Netherlands)

    Timmer-Bonte, J.N.H.; Punt, C.J.A.; Heijden, H.F.M. van der; Die, C.E. van; Bussink, J.; Beijnen, J.H.; Huitema, A.D.; Tjan-Heijnen, V.C.

    2008-01-01

    In advanced non-small cell lung cancer (NSCLC) the clinical benefit of a platinum-based doublet is only modest, therefore, attenuated dosed three-drug combinations are investigated. We hypothesized that with adequate support a full dosed chemotherapy triplet is feasible. The study was designed as a

  20. Evaluation of bioactivity of octacalcium phosphate using osteoblastic cell aggregates on a spheroid culture device

    Directory of Open Access Journals (Sweden)

    Takahisa Anada

    2016-03-01

    Full Text Available Much attention has been paid to three-dimensional cell culture systems in the field of regenerative medicine, since three-dimensional cellular aggregates, or spheroids, are thought to better mimic the in vivo microenvironments compared to conventional monolayer cultured cells. Synthetic calcium phosphate (CaP materials are widely used as bone substitute materials in orthopedic and dental surgeries. Here we have developed a technique for constructing a hybrid spheroid consisting of mesenchymal stem cells (MSCs and synthetic CaP materials using a spheroid culture device. We found that the device is able to generate uniform-sized CaP/cell hybrid spheroids rapidly and easily. The results showed that the extent of osteoblastic differentiation from MSCs was different when cells were grown on octacalcium phosphate (OCP, hydroxyapatite (HA, or β-tricalcium phosphate (β-TCP. OCP showed the greatest ability to increase the alkaline phosphatase activity of the spheroid cells. The results suggest that the spheroids with incorporated OCP may be an effective implantable hybrid consisting of scaffold material and cells for bone regeneration. It is also possible that this CaP–cell spheroid system may be used as an in vitro method for assessing the osteogenic induction ability of CaP materials.

  1. Influence of erythrocyte aggregation at pathological levels on cell-free marginal layer in a narrow circular tube.

    Science.gov (United States)

    Namgung, Bumseok; Sakai, Hiromi; Kim, Sangho

    2015-01-01

    Human red blood cells (RBCs) were perfused in a circular micro-tube (inner diameter of 25 μm) to examine the dynamic changes of cell-free marginal region at both physiological (normal) and pathophysiological (hyper) levels of RBC aggregation. The cell-free area (CFA) was measured to provide additional information on the cell-free layer (CFL) width changes in space and time domains. A prominent enhancement in the mean CFL width was found in hyper-aggregating conditions as compared to that in non-aggregating conditions (P <  0.001). The frequent contacts between RBC and the tube wall were observed and the contact frequency was greatly decreased when the aggregation level was increased from none to normal (P <  0.05) and to hyper (P <  0.001) levels. In addition, the enhanced aggregation from none to hyper levels significantly enlarged the CFA (P <  0.01). We concluded that the RBC aggregation at pathophysiological levels could promote not only the CFL width (one-dimensional parameter) but also the spatiotemporal variation of CFA (two-dimensional parameter).

  2. Optimism as modifier of escalation of commitment.

    Science.gov (United States)

    Juliusson, Asgeir

    2006-10-01

    To study whether optimism-pessimism modifies escalation of commitment, 52 undergraduates were told that they had made an unsuccessful investment, then they chose to continue or discontinue this investment. Optimism about future returns was induced in one group by varying the probability of a successful outcome from an initial low to medium, pessimism was induced in another group by varying this probability from an initial high to medium. Supporting the assumption of the manipulation, the results showed that optimistic participants preferred to continue investments whereas pessimistic participants preferred not to. As predicted, when the sunk cost increased, optimism led to escalation of commitment, whereas pessimism led to de-escalation of commitment. These effects were strengthened when probability of a successful outcome was ambiguous.

  3. Development of a valve-based cell printer for the formation of human embryonic stem cell spheroid aggregates.

    Science.gov (United States)

    Faulkner-Jones, Alan; Greenhough, Sebastian; King, Jason A; Gardner, John; Courtney, Aidan; Shu, Wenmiao

    2013-03-01

    In recent years, the use of a simple inkjet technology for cell printing has triggered tremendous interest and established the field of biofabrication. A key challenge has been the development of printing processes which are both controllable and less harmful, in order to preserve cell and tissue viability and functions. Here, we report on the development of a valve-based cell printer that has been validated to print highly viable cells in programmable patterns from two different bio-inks with independent control of the volume of each droplet (with a lower limit of 2 nL or fewer than five cells per droplet). Human ESCs were used to make spheroids by overprinting two opposing gradients of bio-ink; one of hESCs in medium and the other of medium alone. The resulting array of uniform sized droplets with a gradient of cell concentrations was inverted to allow cells to aggregate and form spheroids via gravity. The resulting aggregates have controllable and repeatable sizes, and consequently they can be made to order for specific applications. Spheroids with between 5 and 140 dissociated cells resulted in spheroids of 0.25-0.6 mm diameter. This work demonstrates that the valve-based printing process is gentle enough to maintain stem cell viability, accurate enough to produce spheroids of uniform size, and that printed cells maintain their pluripotency. This study includes the first analysis of the response of human embryonic stem cells to the printing process using this valve-based printing setup.

  4. Neo-lymphoid aggregates in the adult liver can initiate potent cell-mediated immunity.

    Directory of Open Access Journals (Sweden)

    Melanie Greter

    2009-05-01

    Full Text Available Subcutaneous immunization delivers antigen (Ag to local Ag-presenting cells that subsequently migrate into draining lymph nodes (LNs. There, they initiate the activation and expansion of lymphocytes specific for their cognate Ag. In mammals, the structural environment of secondary lymphoid tissues (SLTs is considered essential for the initiation of adaptive immunity. Nevertheless, cold-blooded vertebrates can initiate potent systemic immune responses even though they lack conventional SLTs. The emergence of lymph nodes provided mammals with drastically improved affinity maturation of B cells. Here, we combine the use of different strains of alymphoplastic mice and T cell migration mutants with an experimental paradigm in which the site of Ag delivery is distant from the site of priming and inflammation. We demonstrate that in mammals, SLTs serve primarily B cell priming and affinity maturation, whereas the induction of T cell-driven immune responses can occur outside of SLTs. We found that mice lacking conventional SLTs generate productive systemic CD4- as well as CD8-mediated responses, even under conditions in which draining LNs are considered compulsory for the initiation of adaptive immunity. We describe an alternative pathway for the induction of cell-mediated immunity (CMI, in which Ag-presenting cells sample Ag and migrate into the liver where they induce neo-lymphoid aggregates. These structures are insufficient to support antibody affinity maturation and class switching, but provide a novel surrogate environment for the initiation of CMI.

  5. Type A behavior pattern and escalating commitment.

    Science.gov (United States)

    Schaubroeck, J; Williams, S

    1993-10-01

    Subjects (N = 98) were randomly assigned to high- and low-responsibility conditions in a commitment-escalation experiment. Global Type A behavior pattern and the underlying dimension of achievement strivings were positively related to the desire to continue the same course of action in the high prior-responsibility condition but not in the low prior-responsibility condition. These findings are discussed in terms of future research into the judgment processes of people with Type A personality and the possible role of escalating commitment in disorders experienced by people with Type A personality.

  6. Production Pattern of Ajmalicine in Catharanthus roseus (L. G. Don. Cell Aggregates Culture in the Airlift Bioreactor

    Directory of Open Access Journals (Sweden)

    RIZKITA RACHMI ESYANTI

    2006-12-01

    Full Text Available A research has been conducted to optimize the rate of aeration and initial weight of cell aggregates in the production of ajmalicine in Catharanthus roseus cell culture in airlift bioreactor. Catharanthus roseus culture were grown in Zenk medium with the addition of 2.50 x 10-6 M naphthalene acetic acid (NAA and 10-5 M benzyl amino purine (BAP. Cell aggregates were sub-cultured two times before transferring 20 and 30 g/fw of cell aggregates into bioreactor, respectively, and aerated with the rate of 0.25 l min-1 and 0.34 l min-1, respectively. The pattern of ajmalicine production in bioreactor were observed in every three days within 24 days. Qualitative and quantitative analysis were conducted using HPLC connected to Cromatopac CL-7A Plus. The results showed that the cell aggregates and medium contain ajmalicine. The highest concentration was obtained in combination of 30 g/fw and 0.34 l min-1 aeration compare to 20 g/fw - 0.25 l min-1, 20 g/fw - 0.34 l min-1, as well as 30 g/fw – 0.25 l min-1. The highest ajmalicine content in cell aggregates was obtained on the 12 days (79.23 µg g-1 whilst in medium was obtained in the 18th days (981.15 µg l-1.

  7. Effect of particle collisions and aggregation on red blood cell passage through a bifurcation.

    Science.gov (United States)

    Chesnutt, J K W; Marshall, J S

    2009-12-01

    Blood flow through bifurcating vessels in the microvasculature leads to uneven distribution of red blood cells (RBC) in the downstream channels when the channels have different sizes or the flow rates through the channels are different. This phenomenon, known as plasma skimming, is responsible for the large variation in hematocrit throughout the circulatory system. Furthermore, the strong streamline curvature present within bifurcations leads to frequent collisions between the blood elements (red and white blood cells and platelets) and the vessel walls, as well as a rearrangement of the distribution of the blood elements in the channels downstream of the bifurcation. Computational models of bifurcation flows typically neglect collision and adhesion of RBCs with each other. In this paper, we use a new type of discrete-element model to investigate the effect of particle-particle collisions and RBC aggregation on modeling of plasma skimming in bifurcations. Cases are examined with and without RBC adhesion and for different hematocrit values, including validation against previous computational results. Results show significant plasma skimming in the low-flow daughter branch and an increase in fractional particle flux with increased hematocrit, as in experimental studies. Accounting for particle-particle collisions leads to a considerable increase in collision rate of particles with the vessel wall. Particles are found to approximately follow fluid velocity streamlines, and consequently particle-particle collisions and aggregation do not significantly affect plasma skimming.

  8. Effect of the LHCII pigment-protein complex aggregation on photovoltaic properties of sensitized TiO2 solar cells.

    Science.gov (United States)

    Yang, Yiqun; Jankowiak, Ryszard; Lin, Chen; Pawlak, Krzysztof; Reus, Michael; Holzwarth, Alfred R; Li, Jun

    2014-10-14

    A modified dye-sensitized solar cell consisting of a thin TiO2 barrier layer sensitized with natural trimeric light-harvesting complex II (LHCII) from spinach was used as a biomimetic model to study the effects of LHCII aggregation on the photovoltaic properties. The aggregation of individual trimers induced molecular reorganization, which dramatically increased the photocurrent. The morphology of small- and large-size LHCII aggregates deposited on a surface was confirmed by atomic force microscopy. Enhanced LHCII immobilization was accomplished via electrostatic interaction with amine-functionalized photoanodes. The photocurrent responses of the assembled solar cells under illumination at three characteristic wavelength bands in the UV-Vis absorption spectra of LHCII solutions confirmed that a significant photocurrent was generated by LHCII photosensitizers. The enhanced photocurrent by large aggregated LHCII is shown to correlate with the quenching in the far-red fluorescence deriving from chlorophyll-chlorophyll charge transfer states that are effectively coupled with the TiO2 surface and thus inject electrons into the TiO2 conduction band. The large aggregated LHCII with more chlorophyll-chlorophyll charge transfer states is a much better sensitizer since it injects electrons more efficiently into the conduction band of TiO2 than the small aggregated LHCII mostly consisting of unquenched chlorophyll excited state. The assembled solar cells demonstrated remarkable stability in both aqueous buffer and acetonitrile electrolytes over 30 days.

  9. Islet-like cell aggregates generated from human adipose tissue derived stem cells ameliorate experimental diabetes in mice.

    Directory of Open Access Journals (Sweden)

    Vikash Chandra

    Full Text Available BACKGROUND: Type 1 Diabetes Mellitus is caused by auto immune destruction of insulin producing beta cells in the pancreas. Currently available treatments include transplantation of isolated islets from donor pancreas to the patient. However, this method is limited by inadequate means of immuno-suppression to prevent islet rejection and importantly, limited supply of islets for transplantation. Autologous adult stem cells are now considered for cell replacement therapy in diabetes as it has the potential to generate neo-islets which are genetically part of the treated individual. Adopting methods of islet encapsulation in immuno-isolatory devices would eliminate the need for immuno-suppressants. METHODOLOGY/PRINCIPAL FINDINGS: In the present study we explore the potential of human adipose tissue derived adult stem cells (h-ASCs to differentiate into functional islet like cell aggregates (ICAs. Our stage specific differentiation protocol permit the conversion of mesodermic h-ASCs to definitive endoderm (Hnf3β, TCF2 and Sox17 and to PDX1, Ngn3, NeuroD, Pax4 positive pancreatic endoderm which further matures in vitro to secrete insulin. These ICAs are shown to produce human C-peptide in a glucose dependent manner exhibiting in-vitro functionality. Transplantation of mature ICAs, packed in immuno-isolatory biocompatible capsules to STZ induced diabetic mice restored near normoglycemia within 3-4 weeks. The detection of human C-peptide, 1155±165 pM in blood serum of experimental mice demonstrate the efficacy of our differentiation approach. CONCLUSIONS: h-ASC is an ideal population of personal stem cells for cell replacement therapy, given that they are abundant, easily available and autologous in origin. Our findings present evidence that h-ASCs could be induced to differentiate into physiologically competent functional islet like cell aggregates, which may provide as a source of alternative islets for cell replacement therapy in type 1 diabetes.

  10. Neurobiology of escalated aggression and violence

    NARCIS (Netherlands)

    Miczek, Klaus A.; de Almeida, Rosa M. M.; Kravitz, Edward A.; Rissman, Emilie F.; de Boer, Sietse F.; Raine, Adrian

    2007-01-01

    Psychopathological violence in criminals and intense aggression in fruit flies and rodents are studied with novel behavioral, neurobiological, and genetic approaches that characterize the escalation from adaptive aggression to violence. One goal is to delineate the type of aggressive behavior and it

  11. Multiscale modeling of bacterial colonies: how pili mediate the dynamics of single cells and cellular aggregates

    Science.gov (United States)

    Pönisch, Wolfram; Weber, Christoph A.; Juckeland, Guido; Biais, Nicolas; Zaburdaev, Vasily

    2017-01-01

    Neisseria gonorrhoeae is the causative agent of one of the most common sexually transmitted diseases, gonorrhea. Over the past two decades there has been an alarming increase of reported gonorrhea cases where the bacteria were resistant to the most commonly used antibiotics thus prompting for alternative antimicrobial treatment strategies. The crucial step in this and many other bacterial infections is the formation of microcolonies, agglomerates consisting of up to several thousands of cells. The attachment and motility of cells on solid substrates as well as the cell-cell interactions are primarily mediated by type IV pili, long polymeric filaments protruding from the surface of cells. While the crucial role of pili in the assembly of microcolonies has been well recognized, the exact mechanisms of how they govern the formation and dynamics of microcolonies are still poorly understood. Here, we present a computational model of individual cells with explicit pili dynamics, force generation and pili-pili interactions. We employ the model to study a wide range of biological processes, such as the motility of individual cells on a surface, the heterogeneous cell motility within the large cell aggregates, and the merging dynamics and the self-assembly of microcolonies. The results of numerical simulations highlight the central role of pili generated forces in the formation of bacterial colonies and are in agreement with the available experimental observations. The model can quantify the behavior of multicellular bacterial colonies on biologically relevant temporal and spatial scales and can be easily adjusted to include the geometry and pili characteristics of various bacterial species. Ultimately, the combination of the microbiological experimental approach with the in silico model of bacterial colonies might provide new qualitative and quantitative insights on the development of bacterial infections and thus pave the way to new antimicrobial treatments.

  12. Alginate encapsulation parameters influence the differentiation of microencapsulated embryonic stem cell aggregates.

    Science.gov (United States)

    Wilson, Jenna L; Najia, Mohamad Ali; Saeed, Rabbia; McDevitt, Todd C

    2014-03-01

    Pluripotent embryonic stem cells (ESCs) have tremendous potential as tools for regenerative medicine and drug discovery, yet the lack of processes to manufacture viable and homogenous cell populations of sufficient numbers limits the clinical translation of current and future cell therapies. Microencapsulation of ESCs within microbeads can shield cells from hydrodynamic shear forces found in bioreactor environments while allowing for sufficient diffusion of nutrients and oxygen through the encapsulation material. Despite initial studies examining alginate microbeads as a platform for stem cell expansion and directed differentiation, the impact of alginate encapsulation parameters on stem cell phenotype has not been thoroughly investigated. Therefore, the objective of this study was to systematically examine the effects of varying alginate compositions on microencapsulated ESC expansion and phenotype. Pre-formed aggregates of murine ESCs were encapsulated in alginate microbeads composed of a high or low ratio of guluronic to mannuronic acid residues (High G and High M, respectively), with and without a poly-L-lysine (PLL) coating, thereby providing four distinct alginate bead compositions for analysis. Encapsulation in all alginate compositions was found to delay differentiation, with encapsulation within High G alginate yielding the least differentiated cell population. The addition of a PLL coating to the High G alginate prevented cell escape from beads for up to 14 days. Furthermore, encapsulation within High M alginate promoted differentiation toward a primitive endoderm phenotype. Taken together, the findings of this study suggest that distinct ESC expansion capacities and differentiation trajectories emerge depending on the alginate composition employed, indicating that encapsulation material physical properties can be used to control stem cell fate.

  13. Aqueous Extract of Paeonia lactiflora and Paeoniflorin as Aggregation Reducers Targeting Chaperones in Cell Models of Spinocerebellar Ataxia 3

    Directory of Open Access Journals (Sweden)

    Kuo-Hsuan Chang

    2013-01-01

    Full Text Available Spinocerebellar ataxia (SCA types 1, 2, 3, 6, 7, and 17 as well as Huntington’s disease are a group of neurodegenerative disorders caused by expanded CAG repeats encoding a long polyglutamine (polyQ tract in the respective proteins. Evidence has shown that the accumulation of intranuclear and cytoplasmic misfolded polyQ proteins leads to apoptosis and cell death. Thus suppression of aggregate formation is expected to inhibit a wide range of downstream pathogenic events in polyQ diseases. In this study, we established a high-throughput aggregation screening system using 293 ATXN3/Q75-GFP cells and applied this system to test the aqueous extract of Paeonia lactiflora (P. lactiflora and its constituents. We found that the aggregation can be significantly prohibited by P. lactiflora and its active compound paeoniflorin. Meanwhile, P. lactiflora and paeoniflorin upregulated HSF1 and HSP70 chaperones in the same cell models. Both of them further reduced the aggregation in neuronal differentiated SH-SY5Y ATXN3/Q75-GFP cells. Our results demonstrate how P. lactiflora and paeoniflorin are likely to work on polyQ-aggregation reduction and provide insight into the possible working mechanism of P. lactiflora in SCA3. We anticipate our paper to be a starting point for screening more potential herbs for the treatment of SCA3 and other polyQ diseases.

  14. Experiment on ``discovery'' STS 51-C: Aggregation of red cells and thrombocytes in heart disease, hyperlipidaemia and other conditions

    Science.gov (United States)

    Dintenfass, L.

    The aim of this experiment was to study aggregation of red cells in the blood of patients with ischaemic heart disease, diabetes, hyperlipidaemia, and (silent) cancer, and in two normal donors. Reconstituted blood using IgG was also used. The instrument, the automated slit-capillary photo-viscometer (100 kg weight) was set on the middeck of the Space Shuttle. An analogous instrument was at the Kennedy Space Center. Blood was obtained from donors, anticoagulated, and adjusted to haematocrit of 30% using native plasma. Experiments took place at 25°C, during which blood was forced to flow in the slit formed by two parallel glass plates. Macro and microphotography was carried out at specific intervals controlled by a computer. During stasis, lasting 6 minutes, aggregates (or clumps) of the red cells were formed. Results indicated that red cell aggregates do form under zero-G; that such aggregates are smaller than the ones obtained at one-G; that morphology is different, the zero-G showing rouleaux while one-G showing usual sludge-like clumps of red cells in all severe disorders. Platelets appeared to remain monodisperse under zero-G. Assuming that these data can be confirmed, one could suggest that zero-G affects cell-cell interaction, and may consequently influence the internal microstructure of the cell membrane and of the receptors, as well as their activity. Gravitational studies may thus open a new door on immunology and haematology in general.

  15. Embryo aggregation does not improve the development of interspecies somatic cell nuclear transfer embryos in the horse.

    Science.gov (United States)

    Gambini, Andrés; De Stéfano, Adrián; Jarazo, Javier; Buemo, Carla; Karlanian, Florencia; Salamone, Daniel Felipe

    2016-09-01

    The low efficiency of interspecies somatic cell nuclear transfer (iSCNT) makes it necessary to investigate new strategies to improve embryonic developmental competence. Embryo aggregation has been successfully applied to improve cloning efficiency in mammals, but it remains unclear whether it could also be beneficial for iSCNT. In this study, we first compared the effect of embryo aggregation over in vitro development and blastocyst quality of porcine, bovine, and feline zona-free (ZF) parthenogenetic (PA) embryos to test the effects of embryo aggregation on species that were later used as enucleated oocytes donors in our iSCNT study. We then assessed whether embryo aggregation could improve the in vitro development of ZF equine iSCNT embryos after reconstruction with porcine, bovine, and feline ooplasm. Bovine- and porcine-aggregated PA blastocysts had significantly larger diameters compared with nonaggregated embryos. On the other hand, feline- and bovine-aggregated PA embryos had higher blastocyst cell number. Embryo aggregation of equine-equine SCNT was found to be beneficial for embryo development as we have previously reported, but the aggregation of three ZF reconstructed embryos did not improve embryo developmental rates on iSCNT. In vitro embryo development of nonaggregated iSCNT was predominantly arrested around the stage when transcriptional activation of the embryonic genome is reported to start on the embryo of the donor species. Nevertheless, independent of embryo aggregation, equine blastocyst-like structures could be obtained in our study using domestic feline-enucleated oocytes. Taken together, these results reported that embryo aggregation enhance in vitro PA embryo development and embryo quality but effects vary depending on the species. Embryo aggregation also improves, as expected, the in vitro embryo development of equine-equine SCNT embryos; however, we did not observe positive effects on equine iSCNT embryo development. Among oocytes

  16. Porphyrin Dye-Sensitized Zinc Oxide Aggregated Anodes for Use in Solar Cells

    Directory of Open Access Journals (Sweden)

    Yu-Kai Syu

    2016-08-01

    Full Text Available Porphyrin YD2-o-C8-based dyes were employed to sensitize room-temperature (RT chemical-assembled ZnO aggregated anodes for use in dye-sensitized solar cells (DSSCs. To reduce the acidity of the YD2-o-C8 dye solution, the proton in the carboxyl group of a porphyrin dye was replaced with tetrabuthyl ammonium (TBA+ in this work. The short-circuit current density (Jsc of the YD2-o-C8-TBA-sensitized ZnO DSSCs is higher than that of the YD2-o-C8-sensitized cells, resulting in the improvement of the efficiency of the YD2-o-C8-based ZnO DSSCs. With an appropriate incorporation of chenodeoxycholic acid (CDCA as coadsorbate, the Jsc and efficiency of the YD2-o-C8-TBA-sensitized ZnO DSSC are enhanced due to the improvement of the incident-photon-to-current efficiency (IPCE values in the wavelength range of 400–450 nm. Moreover, a considerable increase in Jsc is achieved by the addition of a light scattering layer in the YD2-o-C8-TBA-sensitized ZnO photoanodes. Significant IPCE enhancement in the range 475–600 nm is not attainable by tuning the YD2-o-C8-TBA sensitization processes for the anodes without light scattering layers. Using the RT chemical-assembled ZnO aggregated anode with a light scattering layer, an efficiency of 3.43% was achieved in the YD2-o-C8-TBA-sensitized ZnO DSSC.

  17. Weak glycolipid binding of a microdomain-tracer peptide correlates with aggregation and slow diffusion on cell membranes.

    Directory of Open Access Journals (Sweden)

    Tim Lauterbach

    Full Text Available Organized assembly or aggregation of sphingolipid-binding ligands, such as certain toxins and pathogens, has been suggested to increase binding affinity of the ligand to the cell membrane and cause membrane reorganization or distortion. Here we show that the diffusion behavior of the fluorescently tagged sphingolipid-interacting peptide probe SBD (Sphingolipid Binding Domain is altered by modifications in the construction of the peptide sequence that both result in a reduction in binding to ganglioside-containing supported lipid membranes, and at the same time increase aggregation on the cell plasma membrane, but that do not change relative amounts of secondary structural features. We tested the effects of modifying the overall charge and construction of the SBD probe on its binding and diffusion behavior, by Surface Plasmon Resonance (SPR; Biacore analysis on lipid surfaces, and by Fluorescence Correlation Spectroscopy (FCS on live cells, respectively. SBD binds preferentially to membranes containing the highly sialylated gangliosides GT1b and GD1a. However, simple charge interactions of the peptide with the negative ganglioside do not appear to be a critical determinant of binding. Rather, an aggregation-suppressing amino acid composition and linker between the fluorophore and the peptide are required for optimum binding of the SBD to ganglioside-containing supported lipid bilayer surfaces, as well as for interaction with the membrane. Interestingly, the strength of interactions with ganglioside-containing artificial membranes is mirrored in the diffusion behavior by FCS on cell membranes, with stronger binders displaying similar characteristic diffusion profiles. Our findings indicate that for aggregation-prone peptides, aggregation occurs upon contact with the cell membrane, and rather than giving a stronger interaction with the membrane, aggregation is accompanied by weaker binding and complex diffusion profiles indicative of heterogeneous

  18. CD147 and CD98 complex-mediated homotypic aggregation attenuates the CypA-induced chemotactic effect on Jurkat T cells.

    Science.gov (United States)

    Guo, Na; Zhang, Kui; Lv, Minghua; Miao, Jinlin; Chen, Zhinan; Zhu, Ping

    2015-02-01

    Homotypic cell aggregation plays important roles in physiological and pathological processes, including embryogenesis, immune responses, angiogenesis, tumor cell invasion and metastasis. CD147 has been implicated in most of these phenomena, and it was identified as a T cell activation-associated antigen due to its obvious up-regulation in activated T cells. However, the explicit function and mechanism of CD147 in T cells have not been fully elucidated. In this study, large and compact aggregates were observed in Jurkat T cells after treatment with the specific CD147 monoclonal antibody HAb18 or after the expression of CD147 was silenced by RNA interference, which indicated an inhibitory effect of CD147 in T cell homotypic aggregation. Knocking down CD147 expression resulted in a significant decrease in CD98, along with prominent cell aggregation, similar to that treated by CD98 and CD147 monoclonal antibodies. Furthermore, decreased cell chemotactic activity was observed following CD147- and CD98-mediated cell aggregation, and increased aggregation was correlated with a decrease in the chemotactic ability of the Jurkat T cells, suggesting that CD147- and CD98-mediated homotypic cell aggregation plays a negative role in T cell chemotaxis. Our data also showed that p-ERK, p-ZAP70, p-CD3ζ and p-LCK were significantly decreased in the CD147- and CD98-knocked down Jurkat T cells, which suggested that decreased CD147- and/or CD98-induced homotypic T cell aggregation and aggregation-inhibited chemotaxis might be associated with these signaling pathways. A role for CD147 in cell aggregation and chemotaxis was further indicated in primary CD4(+) T cells. Similarly, low expression of CD147 in primary T cells induced prominent cell aggregation and this aggregation attenuated primary T cell chemotactic ability in response to CypA. Our results have demonstrated the correlation between homotypic cell aggregation and the chemotactic response of T cells to CypA, and these data

  19. Simulation of Deformation and Aggregation of Two Red Blood Cells in a Stenosed Microvessel by Dissipative Particle Dynamics.

    Science.gov (United States)

    Xiao, Lanlan; Liu, Yang; Chen, Shuo; Fu, Bingmei

    2016-12-01

    The motion of two red blood cells in a stenosed microvessel was simulated using dissipative particle dynamics. The effects of intercellular interaction, red blood cell deformability and the initial cell orientation on the deformation and aggregation of the RBCs and on the flow resistance were investigated. The red blood cell membrane was treated as a three-dimensional coarse-grained network model and the intercellular interaction was modeled by the Morse potential based on a depletion-mediated assumption. It is shown that the flow resistance increases dramatically when the red blood cells enter into the stenosis and decreases rapidly as RBCs move away from the stenosis. Particularly, for a pair of stiffer red blood cells with the initial inclination angle of 90°, the maximum value of the flow resistance is larger; while a higher flow resistance can also come from a stronger aggregation. For a pair of stiffer red blood cells moving parallel to the main flow, when their positions are closer to the vessel wall at the upstream of the stenosis, the flow resistance increases due to the migration to the vessel center at the stenosis. In addition, for a pair of red blood cells with the initial inclination angle of 0°, the flow resistance from the aggregate formed by a pair of red blood cells with a larger deformation is higher.

  20. Aggregates of nisin with various bactoprenol-containing cell wall precursors differ in size and membrane permeation capacity.

    Science.gov (United States)

    Scherer, Katharina; Wiedemann, Imke; Ciobanasu, Corina; Sahl, Hans-Georg; Kubitscheck, Ulrich

    2013-11-01

    Many lantibiotics use the membrane bound cell wall precursor Lipid II as a specific target for killing Gram-positive bacteria. Binding of Lipid II usually impedes cell wall biosynthesis, however, some elongated lantibiotics such as nisin, use Lipid II also as a docking molecule for pore formation in bacterial membranes. Although the unique nisin pore formation can be analyzed in Lipid II-doped vesicles, mechanistic details remain elusive. We used optical sectioning microscopy to directly visualize the interaction of fluorescently labeled nisin with membranes of giant unilamellar vesicles containing Lipid II and its various bactoprenol precursors. We quantitatively analyzed the binding and permeation capacity of nisin when applied at nanomolar concentrations. Specific interactions with Lipid I, Lipid II and bactoprenol-diphosphate (C55-PP), but not bactoprenol-phosphate (C55-P), resulted in the formation of large molecular aggregates. For Lipid II, we demonstrated the presence of both nisin and Lipid II in these aggregates. Membrane permeation induced by nisin was observed in the presence of Lipid I and Lipid II, but not in the presence of C55-PP. Notably, the size of the C55-PP-nisin aggregates was significantly smaller than that of the aggregates formed with Lipid I and Lipid II. We conclude that the membrane permeation capacity of nisin is determined by the size of the bactoprenol-containing aggregates in the membrane. Notably, transmitted light images indicated that the formation of large aggregates led to a pinch-off of small vesicles, a mechanism, which probably limits the growth of aggregates and induces membrane leakage.

  1. Nuclear Escalation Ladders in South Asia

    Science.gov (United States)

    2011-04-01

    Ibid., pp. 211-212. 23 Fig. 3. Indian Escalation Ladder - Facing China in the Himalayas Response or Initiative Rung Order Thresholds and Rungs Peace...potential land-warfare ladders in the Himalayas . A. Territorial Boundaries India and Pakistan face each other across a common international... Himalayas from Ladakh in Kashmir south and east for 2,100 miles, interrupted by Nepal and Bhutan, which have their own northern borders with China of 768 and

  2. Differential inhibition of tumour cell-induced platelet aggregation by the nicotinate aspirin prodrug (ST0702) and aspirin

    Science.gov (United States)

    Medina, Carlos; Harmon, Shona; Inkielewicz, Iwona; Santos-Martinez, Maria Jose; Jones, Michael; Cantwell, Paula; Bazou, Despina; Ledwidge, Mark; Radomski, Marek W; Gilmer, John F

    2012-01-01

    BACKGROUND AND PURPOSE Tumour cell-induced platelet aggregation (TCIPA) facilitates cancer cell invasion, angiogenesis and the formation of metastatic foci. TCIPA can be modulated by pharmacological inhibitors of MMP-2 and ADP; however, the COX inhibitor aspirin did not prevent TCIPA. In this study, we have tested the pharmacological effects of a new group of isosorbide-based aspirin prodrugs on TCIPA. EXPERIMENTAL APPROACH TCIPA was induced in human platelets by mixing with human adenocarcinoma or fibrosarcoma cells under no flow and flow conditions. The release of gelatinases and P-selectin expression during TCIPA were studied by zymography and flow cytometry respectively. KEY RESULTS Tumour cells caused platelet aggregation. This aggregation resulted in the release of MMP-2 and a significant up-regulation of P-selectin on platelets, indicative of platelet activation. Pharmacological modulation of TCIPA revealed that ST0702, one of the aspirin prodrugs, down-regulated TCIPA while aspirin was ineffective. The deacetylated metabolite of ST0702, 5-nicotinate salicylate (ST0702 salicylate), down-regulated both ADP-stimulated platelet aggregation and TCIPA. CONCLUSIONS AND IMPLICATIONS Our results show that ST0702 was an effective inhibitor of TCIPA in vitro. Its deacetylated metabolite may contribute to the effects of ST0702 by inhibiting ADP-mediated TCIPA. PMID:22122360

  3. Conservation of root regeneration potential of cell aggregates from horseradish hairy roots used as artificial seeds

    Energy Technology Data Exchange (ETDEWEB)

    Repunte, V.; Taya, M.; Tone, S. [Osaka University, Osaka (Japan). Faculty of Engineering Science

    1996-10-20

    The effects of water content in agar gel used as a medium and oxygen level in the gas phase on the adventitious root regeneration of cell aggregates (CA) derived from horseradish hairy roots were investigated in cultures at 25{degree}C. The number of roots emerging from CA was highly dependent on water content of the agar gel and no root regeneration was observed at a gel water content of 66% during culture time of 20 days. CA root regeneration was suppressed when the CA were kept for 20 days in an atmosphere oxygen composition of 10%, but was restored upon transfer of the CA to normal atmosphere of 21% oxygen. On the basis of these findings, an artificial seed was proposed using the CA as a cell inclusion material encapsulated in alginate gels covered with coats. From the perspective of conserving the root regeneration potential of the CA by preventing the drying of alginate gel while keeping oxygen availability to the CA, different coating materials of ethylene vinyl acetate acrylic acid terpolymer, paraffin and polyorganosiloxane were tested. Paraffin was selected as a suitable coating material because of its efficient drying tolerance and adequate permeability to oxygen. A regeneration efficiency of 90% could be obtained from the CA, stored in alginate gel covered with a paraffin coating of 0.40 mm thickness at 25{degree}C for 60 days in air, when sucrose concentration in the gel was over 240 mol m{sup -3}. 25 refs., 8 figs.

  4. Physical enviroment of 2-D animal cell aggregates formed in a short pathlength ultrasound standing wave trap.

    Science.gov (United States)

    Bazou, Despina; Kuznetsova, Larisa A; Coakley, W Terence

    2005-03-01

    2-D mammalian cell aggregates can be formed and levitated in a 1.5 MHz single half wavelength ultrasound standing wave trap. The physical environment of cells in such a trap has been examined. Attention was paid to parameters such as temperature, acoustic streaming, cavitation and intercellular forces. The extent to which these factors might be intrusive to a neural cell aggregate levitated in the trap was evaluated. Neural cells were exposed to ultrasound at a pressure amplitude of 0.54 MPa for 30 s; a small aggregate had been formed at the center of the trap. The pressure amplitude was then decreased to 0.27 MPa for 2 min, at which level the aggregation process continued at a slower rate. The pressure amplitude was then decreased to 0.06 MPa for 1 h. Temperature measurements that were conducted in situ with a 200 microm thermocouple over a 30 min period showed that the maximum temperature rise was less than 0.5 K. Acoustic streaming was measured by the particle image velocimetry method (PIV). It was shown that the hydrodynamic stress imposed on cells by acoustic streaming is less than that imposed by gentle preparative centrifugation procedures. Acoustic spectrum analysis showed that cavitation activity does not occur in the cell suspensions sonicated at the above pressures. White noise was detected only at a pressure amplitude of 1.96 MPa. Finally, it was shown that the attractive acoustic force between ultrasonically agglomerated cells is small compared with the normal attractive van der Waals force that operates at close cell surface separations. It is concluded that the standing wave trap operates only to concentrate cells locally, as in tissue, and does not modify the in vitro expression of surface receptor interactions.

  5. Magnetic engineering of stable rod-shaped stem cell aggregates: circumventing the pitfall of self-bending.

    Science.gov (United States)

    Du, V; Fayol, D; Reffay, M; Luciani, N; Bacri, J-C; Gay, C; Wilhelm, C

    2015-02-01

    A current challenge for tissue engineering while restoring the function of diseased or damaged tissue is to customize the tissue according to the target area. Scaffold-free approaches usually yield spheroid shapes with the risk of necrosis at the center due to poor nutrient and oxygen diffusion. Here, we used magnetic forces developed at the cellular scale by miniaturized magnets to create rod-shaped aggregates of stem cells that subsequently matured into a tissue-like structure. However, during the maturation process, the tissue-rods spontaneously bent and coiled into sphere-like structures, triggered by the increasing cell-cell adhesion within the initially non-homogeneous tissue. Optimisation of the intra-tissular magnetic forces successfully hindered the transition, in order to produce stable rod-shaped stem cells aggregates.

  6. Antigen 43 from Escherichia coli induces inter- and intraspecies cell aggregation and changes in colony morphology of Pseudomonas fluorescens

    DEFF Research Database (Denmark)

    Kjærgaard, Kristian; Schembri, Mark; Hasman, Henrik;

    2000-01-01

    Antigen 43 (Ag43) is a surface-displayed autotransporter protein of Escherichia coli. By virtue of its self-association characteristics, this protein is able to mediate autoaggregation and flocculation off. coli cells in static cultures. Additionally, surface display of Ag43 is associated...... with a distinct frizzy colony morphology in E. coli. Here we show that Ag43 can be expressed in a functional form on the surface of the environmentally important Pseudomonas fluorescens strain SBW25 with ensuing cell aggregation and frizzy colony types. Using green fluorescence protein-tagged cells, we...... demonstrate that Ag43 can be used as a tool to provide interspecies cell aggregation between E. coli and P. fluorescens. Furthermore, Ag43 expression enhances biofilm formation in P. fluorescens to glass surfaces. The versatility of this protein was also reflected in Ag43 surface display in a variety of other...

  7. In vitro aggregation behavior of a non-amyloidogenic λ light chain dimer deriving from U266 multiple myeloma cells.

    Directory of Open Access Journals (Sweden)

    Paolo Arosio

    Full Text Available Excessive production of monoclonal light chains due to multiple myeloma can induce aggregation-related disorders, such as light chain amyloidosis (AL and light chain deposition diseases (LCDD. In this work, we produce a non-amyloidogenic IgE λ light chain dimer from human mammalian cells U266, which originated from a patient suffering from multiple myeloma, and we investigate the effect of several physicochemical parameters on the in vitro stability of this protein. The dimer is stable in physiological conditions and aggregation is observed only when strong denaturating conditions are applied (acidic pH with salt at large concentration or heating at melting temperature T(m at pH 7.4. The produced aggregates are spherical, amorphous oligomers. Despite the larger β-sheet content of such oligomers with respect to the native state, they do not bind Congo Red or ThT. The impossibility to obtain fibrils from the light chain dimer suggests that the occurrence of amyloidosis in patients requires the presence of the light chain fragment in the monomer form, while dimer can form only amorphous oligomers or amorphous deposits. No aggregation is observed after denaturant addition at pH 7.4 or at pH 2.0 with low salt concentration, indicating that not a generic unfolding but specific conformational changes are necessary to trigger aggregation. A specific anion effect in increasing the aggregation rate at pH 2.0 is observed according to the following order: SO(4(-≫Cl(->H(2PO(4(-, confirming the peculiar role of sulfate in promoting protein aggregation. It is found that, at least for the investigated case, the mechanism of the sulfate effect is related to protein secondary structure changes induced by anion binding.

  8. In vitro aggregation behavior of a non-amyloidogenic λ light chain dimer deriving from U266 multiple myeloma cells.

    Science.gov (United States)

    Arosio, Paolo; Owczarz, Marta; Müller-Späth, Thomas; Rognoni, Paola; Beeg, Marten; Wu, Hua; Salmona, Mario; Morbidelli, Massimo

    2012-01-01

    Excessive production of monoclonal light chains due to multiple myeloma can induce aggregation-related disorders, such as light chain amyloidosis (AL) and light chain deposition diseases (LCDD). In this work, we produce a non-amyloidogenic IgE λ light chain dimer from human mammalian cells U266, which originated from a patient suffering from multiple myeloma, and we investigate the effect of several physicochemical parameters on the in vitro stability of this protein. The dimer is stable in physiological conditions and aggregation is observed only when strong denaturating conditions are applied (acidic pH with salt at large concentration or heating at melting temperature T(m) at pH 7.4). The produced aggregates are spherical, amorphous oligomers. Despite the larger β-sheet content of such oligomers with respect to the native state, they do not bind Congo Red or ThT. The impossibility to obtain fibrils from the light chain dimer suggests that the occurrence of amyloidosis in patients requires the presence of the light chain fragment in the monomer form, while dimer can form only amorphous oligomers or amorphous deposits. No aggregation is observed after denaturant addition at pH 7.4 or at pH 2.0 with low salt concentration, indicating that not a generic unfolding but specific conformational changes are necessary to trigger aggregation. A specific anion effect in increasing the aggregation rate at pH 2.0 is observed according to the following order: SO(4)(-)≫Cl(-)>H(2)PO(4)(-), confirming the peculiar role of sulfate in promoting protein aggregation. It is found that, at least for the investigated case, the mechanism of the sulfate effect is related to protein secondary structure changes induced by anion binding.

  9. Aggregation of gold nanoparticles followed by methotrexate release enables Raman imaging of drug delivery into cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Durgadas, C. V.; Sharma, C. P.; Paul, W.; Rekha, M. R. [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Biosurface Technology Division (India); Sreenivasan, K., E-mail: sreeni@sctimst.ac.in [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Laboratory for Polymer Analysis, Biomedical Technology Wing (India)

    2012-09-15

    This study refers an aqueous synthesis of methotrexate (MTX)-conjugated gold nanoparticles (GNPs), their interaction with HepG2 cells, and the use of Raman imaging to observe cellular internalization and drug delivery. GNPs of average size 3.5-5 nm were stabilized using the amine terminated bifunctional biocompatible copolymer and amended by conjugating MTX, an anticancer drug. The nanoparticles were released MTX at a faster rate in acidic pH and subsequently found to form aggregates. The Raman signals of cellular components were found to be enhanced by the aggregated particles enabling the mapping to visualize site-specific drug delivery. The methodology seems to have potential in optimizing the characteristics of nanodrug carriers for emptying the cargo precisely at specified sites.Graphical AbstractDrug release induced particle aggregation enhances Raman signals to aid in imaging.

  10. Homotypic aggregation of human cell lines by HLA class II-, class Ia- and HLA-G-specific monoclonal antibodies

    DEFF Research Database (Denmark)

    Odum, Niels; Ledbetter, J A; Martin, P

    1991-01-01

    adhesion between T and B cells by activating the CD18/CD11a (LFA-1) adhesion pathway. Here we report that monoclonal antibodies (mAb) against HLA-DR (L243, p4.1, HB10a, VI15) and certain broad class II reacting mAb (TU35, TU39), but not anti-DQ (TU22, Leu-10) mAb, induced homotypic aggregation of human......, but not the class I-negative parental line, 221, showed homotypic aggregation in response to an HLA-G specific mAb (87G) and a broad reacting class I-specific mAb (IOT2). Both cell lines responded with aggregation to anti-class II mAb (TU35). The anti-class I mAb, W6/32, had no effect on all cell lines tested...... and two anti-beta 2-microglobulin mAb had variable, weak effects. The aggregation response was an active, temperature-sensitive process which was almost totally abrogated by azide and by cytochalasins B and E, but unaffected by colchicine, EDTA, aphidicolin, actinomycin D and protein tyrosine kinase...

  11. Extracellular polysaccharide composition of Azospirillum brasilense and its relation with cell aggregation.

    Science.gov (United States)

    Burdman, S; Jurkevitch, E; Soria-Díaz, M E; Serrano, A M; Okon, Y

    2000-08-15

    The exopolysaccharide (EPS) and capsular polysaccharide (CPS) composition of four Azospirillum brasilense strains differing in their aggregation capacity was analyzed by high performance anion exchange chromatography. When growing the different strains in an aggregation inducing medium containing a high carbon:nitrogen (C:N) ratio, both EPS and CPS showed a positive correlation between aggregation and the relative amount of arabinose. Arabinose was not detected in polysaccharides from Sp72002, a pleiotrophic Tn5 mutant strain impaired in aggregation. Arabinose was also not detected in extracellular polysaccharides of bacteria grown in a low C:N ratio, non-inducing aggregation medium, with exception for a relatively small amount found in the CPS of FAJ0204, a super-aggregating mutant strain. The only monosaccharides able to significantly inhibit aggregation at low sugar concentration when tested in a bioassay were arabinose (at a higher extent) and galactose. The possibility that residues of arabinose present in the extracellular polysaccharides are involved in the aggregation of A. brasilense is discussed.

  12. Influence of Mechanical Cell Salvage on Red Blood Cell Aggregation, Deformability, and 2,3-Diphosphoglycerate in Patients Undergoing Cardiac Surgery With Cardiopulmonary Bypass

    NARCIS (Netherlands)

    Gu, Y. John; Vermeijden, Wytze J.; de Vries, Adrianus J.; Hagenaars, J. Ans M.; Graaff, Reindert; van Oeveren, Willem

    2008-01-01

    Background. Mechanical cell salvage is increasingly used during cardiac surgery. Although this procedure is considered safe, it is unknown whether it affects the red blood cell (RBC) function, especially the RBC aggregation, deformability, and the contents of 2,3-diphosphoglycerate (2,3-DPG). This s

  13. From single cell mechanics and intercellular forces to collective aggregate dynamics Individual cell-based modeling of cell cultures for tissue engineering

    OpenAIRE

    Smeets, Bart

    2016-01-01

    The mechanisms that biological cells exploit to organize themselves into multicellular aggregates and tissue-like structures are based on fundamental physical principles. Yet, the natural emergence of complexity in biological systems, while of great importance for many applications in biology and medicine, is still poorly understood. For this, mathematical models can be of great help by identifying key components and mechanisms that govern a system, and based on these, predict the inception o...

  14. Reversal of a full-length mutant huntingtin neuronal cell phenotype by chemical inhibitors of polyglutamine-mediated aggregation

    Directory of Open Access Journals (Sweden)

    MacDonald Marcy E

    2005-01-01

    Full Text Available Abstract Background Huntington's disease (HD is an inherited neurodegenerative disorder triggered by an expanded polyglutamine tract in huntingtin that is thought to confer a new conformational property on this large protein. The propensity of small amino-terminal fragments with mutant, but not wild-type, glutamine tracts to self-aggregate is consistent with an altered conformation but such fragments occur relatively late in the disease process in human patients and mouse models expressing full-length mutant protein. This suggests that the altered conformational property may act within the full-length mutant huntingtin to initially trigger pathogenesis. Indeed, genotype-phenotype studies in HD have defined genetic criteria for the disease initiating mechanism, and these are all fulfilled by phenotypes associated with expression of full-length mutant huntingtin, but not amino-terminal fragment, in mouse models. As the in vitro aggregation of amino-terminal mutant huntingtin fragment offers a ready assay to identify small compounds that interfere with the conformation of the polyglutamine tract, we have identified a number of aggregation inhibitors, and tested whether these are also capable of reversing a phenotype caused by endogenous expression of mutant huntingtin in a striatal cell line from the HdhQ111/Q111 knock-in mouse. Results We screened the NINDS Custom Collection of 1,040 FDA approved drugs and bioactive compounds for their ability to prevent in vitro aggregation of Q58-htn 1–171 amino terminal fragment. Ten compounds were identified that inhibited aggregation with IC50 HdhQ111/Q111 striatal cells. Conclusions At least some compounds identified as aggregation inhibitors also prevent a neuronal cellular phenotype caused by full-length mutant huntingtin, suggesting that in vitro fragment aggregation can act as a proxy for monitoring the disease-producing conformational property in HD. Thus, identification and testing of compounds that

  15. De-Escalating the IT-Projects

    Directory of Open Access Journals (Sweden)

    Ghulam Muhammad Kundi

    2007-12-01

    Full Text Available Escalation stickins with an ailing project beyond rational justifications. This happens because in the face of negative feedback, decision makers are strangled between whether to stick with or quit the dying project. Environmental uncertainty has been identified as the root cause of the escalatory behavior. This uncertainty emanates from several sources relating to individual, group, organization and broader environmental factors. This paper argues the premise that effective communication can help create an environment whereby workforce can develop an organized action thereby distributing the responsibility across the whole workforce and not the individuals – leading to the possible reduction of escalatory behavior in IT projects.

  16. A particle-based model to simulate the micromechanics of single-plant parenchyma cells and aggregates.

    Science.gov (United States)

    Van Liedekerke, P; Ghysels, P; Tijskens, E; Samaey, G; Smeedts, B; Roose, D; Ramon, H

    2010-05-26

    This paper is concerned with addressing how plant tissue mechanics is related to the micromechanics of cells. To this end, we propose a mesh-free particle method to simulate the mechanics of both individual plant cells (parenchyma) and cell aggregates in response to external stresses. The model considers two important features in the plant cell: (1) the cell protoplasm, the interior liquid phase inducing hydrodynamic phenomena, and (2) the cell wall material, a viscoelastic solid material that contains the protoplasm. In this particle framework, the cell fluid is modeled by smoothed particle hydrodynamics (SPH), a mesh-free method typically used to address problems with gas and fluid dynamics. In the solid phase (cell wall) on the other hand, the particles are connected by pairwise interactions holding them together and preventing the fluid to penetrate the cell wall. The cell wall hydraulic conductivity (permeability) is built in as well through the SPH formulation. Although this model is also meant to be able to deal with dynamic and even violent situations (leading to cell wall rupture or cell-cell debonding), we have concentrated on quasi-static conditions. The results of single-cell compression simulations show that the conclusions found by analytical models and experiments can be reproduced at least qualitatively. Relaxation tests revealed that plant cells have short relaxation times (1 micros-10 micros) compared to mammalian cells. Simulations performed on cell aggregates indicated an influence of the cellular organization to the tissue response, as was also observed in experiments done on tissues with a similar structure.

  17. MULTICELLULAR-MEDIATED EXPRESSION OF P-GP AND MRP AND RELATIONSHIP WITH CELL CYCLE PROFILES IN HUMAN OVARIAN CANCER SK-OV-3ip1 MULTICELLULAR AGGREGATES

    Institute of Scientific and Technical Information of China (English)

    陈建利; 丰有吉; 张琴

    2001-01-01

    To investigate the expression of P-glycoprotein (P-gp) and multidrug resistance- associated protein (MRP) and the relationship with cell cycle profiles in ovarian cancer SK-OV-3ip1 multicellular aggregates. Methods: Liquid overlay system was employed to obtain multicellular aggregates. Expression of P-gp and MRP was detected with flow cytometry (FCM). Outer, intermediate and inner cells from multicellular aggregates were collected by layer-trypsinized method. Cell cycle profiles were also analyzed by FCM. Results: Compared with control cells, no expression of P-gp and MRP was detected in monolyer cells (P=0.128 and P=0.604), but expression of P-gp and MRP in aggregate cells was significantly elevated (P<0.01). P-gp expression in every layer cells was also obviously increased (P<0.01). Furthermore, P-gp expression in every layer cells was also obviously increased (P=0.071). Tendency to increased G0-G1 phase and reduced S phase cells existed from outer through intermediate to inner layers in multicellular aggregates but with no statistical difference. Cell percentages in G2-M phase also had no difference. However, compared with monolayer cells, cells in G0-G1 phase increased and cells in S and G2-M phases lowered significantly in every layer and in the whole multicellular aggregates. Expression elevation of P-gp and MRP was consistent with increased G0-G1 percentage in aggregate cells. Conclusion: Expression of P-gp and MRP increases in cells of SK-OV-3ip1 multicellular aggregates and is consistent with increased G0-G1 percentage, which implies the possible relationship between them and the possible role in multicellular-mediated drug resistance.

  18. Men with Sickle Cell Anemia and Priapism Exhibit Increased Hemolytic Rate, Decreased Red Blood Cell Deformability and Increased Red Blood Cell Aggregate Strength.

    Directory of Open Access Journals (Sweden)

    Kizzy-Clara Cita

    Full Text Available To investigate the association between priapism in men with sickle cell anemia (SCA and hemorheological and hemolytical parameters.Fifty-eight men with SCA (median age: 38 years were included; 28 who had experienced priapism at least once during their life (priapism group and 30 who never experienced this complication (control group. Twenty-two patients were treated with hydroxycarbamide, 11 in each group. All patients were at steady state at the time of inclusion. Hematological and biochemical parameters were obtained through routine procedures. The Laser-assisted Optical Rotational Cell Analyzer was used to measure red blood cell (RBC deformability at 30 Pa (ektacytometry and RBC aggregation properties (laser backscatter versus time. Blood viscosity was measured at a shear rate of 225 s-1 using a cone/plate viscometer. A principal component analysis was performed on 4 hemolytic markers (i.e., lactate dehydrogenase (LDH, aspartate aminotransferase (ASAT, total bilirubin (BIL levels and reticulocyte (RET percentage to calculate a hemolytic index.Compared to the control group, patients with priapism exhibited higher ASAT (p = 0.01, LDH (p = 0.03, RET (p = 0.03 levels and hemolytic indices (p = 0.02. Higher RBC aggregates strength (p = 0.01 and lower RBC deformability (p = 0.005 were observed in patients with priapism compared to controls. After removing the hydroxycarbamide-treated patients, RBC deformability (p = 0.01 and RBC aggregate strength (p = 0.03 were still different between the two groups, and patients with priapism exhibited significantly higher hemolytic indices (p = 0.01 than controls.Our results confirm that priapism in SCA is associated with higher hemolytic rates and show for the first time that this complication is also associated with higher RBC aggregate strength and lower RBC deformability.

  19. Tobacco and the Escalating Global Cancer Burden

    Directory of Open Access Journals (Sweden)

    Richard F. Oppeltz

    2011-01-01

    Full Text Available The global burden of cancer is escalating as a result of dramatic increases in the use of tobacco in the developing world. The use of tobacco is linked to the development of a broad variety of cancers, mainly lung cancer, the single most common cancer in the world. Tobacco smoking-attributable deaths extends beyond cancer and include stroke, heart attack and COPD. Widening disparities in cancer-related mortality have shifted towards a more dramatic burden in the developing world. Appropriate interventions must be implemented to reduce tobacco use and prevent global mortality that has escalated to epidemic levels. Tobacco control policies, including public health advertisement campaigns, warning labels, adoption of smoke-free laws, comprehensive bans and tax policies are highly effective measures to control tobacco use. Clinicians and academic institutions have to be actively committed to support tobacco control initiatives. The reduction in cancer related morbidity and mortality should be viewed as a global crisis and definitive results will depend on a multilevel effort to effectively reduce the burden of cancer, particularly in underprivileged regions of the world.

  20. Dose escalation of a curcuminoid formulation

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    Crowell James

    2006-03-01

    Full Text Available Abstract Background Curcumin is the major yellow pigment extracted from turmeric, a commonly-used spice in India and Southeast Asia that has broad anticarcinogenic and cancer chemopreventive potential. However, few systematic studies of curcumin's pharmacology and toxicology in humans have been performed. Methods A dose escalation study was conducted to determine the maximum tolerated dose and safety of a single dose of standardized powder extract, uniformly milled curcumin (C3 Complex™, Sabinsa Corporation. Healthy volunteers were administered escalating doses from 500 to 12,000 mg. Results Seven of twenty-four subjects (30% experienced only minimal toxicity that did not appear to be dose-related. No curcumin was detected in the serum of subjects administered 500, 1,000, 2,000, 4,000, 6,000 or 8,000 mg. Low levels of curcumin were detected in two subjects administered 10,000 or 12,000 mg. Conclusion The tolerance of curcumin in high single oral doses appears to be excellent. Given that achieving systemic bioavailability of curcumin or its metabolites may not be essential for colorectal cancer chemoprevention, these findings warrant further investigation for its utility as a long-term chemopreventive agent.

  1. Mild exposure of RIN-5F β-cells to human islet amyloid polypeptide aggregates upregulates antioxidant enzymes via NADPH oxidase-RAGE: An hormetic stimulus

    Directory of Open Access Journals (Sweden)

    Elisabetta Borchi

    2014-01-01

    Full Text Available The presence of amyloid aggregates of human islet amyloid polypeptide (hIAPP, a hallmark of type 2 diabetes, contributes to pancreatic β-cell impairment, where oxidative stress plays a key role. A contribution of NADPH oxidase to reactive oxygen species (ROS generation after cell exposure to micromolar concentrations of hIAPP aggregates has been suggested. However, little is known about β-cells exposure to lower amounts of hIAPP aggregates, similar to those found in human pancreas. Thus, we aimed to investigate the events resulting from RIN-5F cells exposure to nanomolar concentrations of toxic hIAPP aggregates. We found an early and transient rise of NADPH oxidase activity resulting from increased Nox1 expression following the engagement of receptor for advanced glycation end-products (RAGE by hIAPP aggregates. Unexpectedly, NADPH oxidase activation was not accompanied by a significant ROS increase and the lipoperoxidation level was significantly reduced. Indeed, cell exposure to hIAPP aggregates affected the antioxidant defences, inducing a significant increase of the expression and activity of catalase and glutathione peroxidase. We conclude that exposure of pancreatic β-cells to nanomolar concentrations of hIAPP aggregates for a short time induces an hormetic response via the RAGE-Nox1 axis; the latter stimulates the enzymatic antioxidant defences that preserve the cells against oxidative stress damage.

  2. Soluble aggregates of the amyloid-β peptide are trapped by serum albumin to enhance amyloid-β activation of endothelial cells

    Directory of Open Access Journals (Sweden)

    Gonzalez-Velasquez Francisco J

    2009-04-01

    Full Text Available Abstract Background Self-assembly of the amyloid-β peptide (Aβ has been implicated in the pathogenesis of Alzheimer's disease (AD. As a result, synthetic molecules capable of inhibiting Aβ self-assembly could serve as therapeutic agents and endogenous molecules that modulate Aβ self-assembly may influence disease progression. However, increasing evidence implicating a principal pathogenic role for small soluble Aβ aggregates warns that inhibition at intermediate stages of Aβ self-assembly may prove detrimental. Here, we explore the inhibition of Aβ1–40 self-assembly by serum albumin, the most abundant plasma protein, and the influence of this inhibition on Aβ1–40 activation of endothelial cells for monocyte adhesion. Results It is demonstrated that serum albumin is capable of inhibiting in a dose-dependent manner both the formation of Aβ1–40 aggregates from monomeric peptide and the ongoing growth of Aβ1–40 fibrils. Inhibition of fibrillar Aβ1–40 aggregate growth is observed at substoichiometric concentrations, suggesting that serum albumin recognizes aggregated forms of the peptide to prevent monomer addition. Inhibition of Aβ1–40 monomer aggregation is observed down to stoichiometric ratios with partial inhibition leading to an increase in the population of small soluble aggregates. Such partial inhibition of Aβ1–40 aggregation leads to an increase in the ability of resulting aggregates to activate endothelial cells for adhesion of monocytes. In contrast, Aβ1–40 activation of endothelial cells for monocyte adhesion is reduced when more complete inhibition is observed. Conclusion These results demonstrate that inhibitors of Aβ self-assembly have the potential to trap small soluble aggregates resulting in an elevation rather than a reduction of cellular responses. These findings provide further support that small soluble aggregates possess high levels of physiological activity and underscore the importance of

  3. Enhancement of cell adhesion, retention, and survival of HUVEC/cbMSC aggregates that are transplanted in ischemic tissues by concurrent delivery of an antioxidant for therapeutic angiogenesis.

    Science.gov (United States)

    Huang, Chieh-Cheng; Pan, Wen-Yu; Tseng, Michael T; Lin, Kun-Ju; Yang, Yi-Pei; Tsai, Hung-Wen; Hwang, Shiaw-Min; Chang, Yen; Wei, Hao-Ji; Sung, Hsing-Wen

    2016-01-01

    A recurring obstacle in cell-base strategies for treating ischemic diseases is the significant loss of viable cells that is caused by the elevated levels of regional reactive oxygen species (ROS), which ultimately limits therapeutic capacity. In this study, aggregates of human umbilical vein endothelial cells (HUVECs) and cord-blood mesenchymal stem cells (cbMSCs), which are capable of inducing therapeutic angiogenesis, are prepared. We hypothesize that the concurrent delivery of an antioxidant N-acetylcysteine (NAC) may significantly increase cell retention following the transplantation of HUVEC/cbMSC aggregates in a mouse model with hindlimb ischemia. Our in vitro results demonstrate that the antioxidant NAC can restore ROS-impaired cell adhesion and recover the reduced angiogenic potential of HUVEC/cbMSC aggregates under oxidative stress. In the animal study, we found that by scavenging the ROS generated in ischemic tissues, NAC is likely to be able to establish a receptive cell environment in the early stage of cell transplantation, promoting the adhesion, retention, and survival of cells of engrafted aggregates. Therapeutic angiogenesis is therefore enhanced and blood flow recovery and limb salvage are ultimately achieved. The combinatory strategy that uses an antioxidant and HUVEC/cbMSC aggregates may provide a new means of boosting the therapeutic efficacy of cell aggregates for the treatment of ischemic diseases.

  4. Symmetry recovery of cell-free layer after bifurcations of small arterioles in reduced flow conditions: effect of RBC aggregation.

    Science.gov (United States)

    Ng, Yan Cheng; Namgung, Bumseok; Tien, Sim Leng; Leo, Hwa Liang; Kim, Sangho

    2016-08-01

    Heterogeneous distribution of red blood cells (RBCs) in downstream vessels of arteriolar bifurcations can be promoted by an asymmetric formation of cell-free layer (CFL) in upstream vessels. Consequently, the CFL widths in subsequent downstream vessels become an important determinant for tissue oxygenation (O2) and vascular tone change by varying nitric oxide (NO) availability. To extend our previous understanding on the formation of CFL in arteriolar bifurcations, this study investigated the formation of CFL widths from 2 to 6 vessel-diameter (2D-6D) downstream of arteriolar bifurcations in the rat cremaster muscle (D = 51.5 ± 1.3 μm). As the CFL widths are highly influenced by RBC aggregation, the degree of aggregation was adjusted to simulate levels seen during physiological and pathological states. Our in vivo experimental results showed that the asymmetry of CFL widths persists along downstream vessels up to 6D from the bifurcating point. Moreover, elevated levels of RBC aggregation appeared to retard the recovery of CFL width symmetry. The required length of complete symmetry recovery was estimated to be greater than 11D under reduced flow conditions, which is relatively longer than interbifurcation distances of arterioles for vessel diameter of ∼50 μm. In addition, our numerical prediction showed that the persistent asymmetry of CFL widths could potentially result in a heterogeneous vasoactivity over the entire arteriolar network in such abnormal flow conditions.

  5. Extract from Aronia melanocarpa fruits potentiates the inhibition of platelet aggregation in the presence of endothelial cells

    Science.gov (United States)

    Luzak, Boguslawa; Golanski, Jacek; Rozalski, Marek; Krajewska, Urszula; Olas, Beata

    2010-01-01

    Introduction Some polyphenolic compounds extracted from Aronia melanocarpa fruits (AM) have been reported to be cardioprotective agents. In this study we evaluated the ability of AM extract to increase the efficacy of human umbilical vein endothelial cells (HUVECs) to inhibit platelet functions in vitro. Material and methods This study encompasses two models of monitoring platelet reactivity: optical aggregation and platelet degranulation (monitored as the surface CD62P expression) in PRP upon the stimulation with ADP. Results We observed that only at low concentrations (5 µg/ml) did AM extract significantly improve antiplatelet action of HUVECs towards ADP-activated platelets in the aggregation test. Conclusions It is concluded that the potentiating effect of AM extract on the endothelial cell-mediated inhibition of platelet aggregation clearly depends on the used concentrations of Aronia-derived active compounds. Therefore, despite these encouraging preliminary outcomes on the beneficial effects of AM extract polyphenols, more profound dose-effect studies should certainly be considered before the implementation of Aronia-originating compounds in antiplatelet therapy and the prevention of cardiovascular diseases. PMID:22371737

  6. Effect of Aggregated β-Amyloid (1-42 on Synaptic Plasticity of Hippocampal Dentate Gyrus Granule Cells in Vivo

    Directory of Open Access Journals (Sweden)

    Shirin Babri

    2012-12-01

    Full Text Available Introduction: Alzheimer’s disease (AD is a common neurodegenerative disorder in elderly people with an impairment of cognitive decline and memory loss. β-amyloid (Aβ as a potent neurotoxic peptide has a pivotal role in the pathogenesis of AD. This disease begins with impairment in synaptic functions before developing into later neuro­degeneration and neuronal loss. The aim of this study was to evaluate the synaptic plasticity and electrophysiological function of granule cells in hippocampal dentate gyrus (DG after intracerebroventricular (i.c.v. administration of aggregated Aβ (1-42 peptide in vivo. Methods: Animals were divided to control and Aβ (1-42 groups. Long-term potentia­tion (LTP in perforant path-DG synapses was assessed in order to investigate the effect of aggregated Aβ (1-42 on synaptic plasticity. Field excitatory post-synaptic potential (fEPSP slope and population spike (PS amplitude were measured. Results: Administration of Aβ (1-42 significantly decreased fEPSP slope and PS amplitude in Aβ (1-42 group comparing with the control group and had no effect on baseline activity of neurons. Conclusion: The present study indicates that administration of aggregated form of Aβ (1-42 into the lateral ventricle effectively inhibits LTP in granular cells of the DG in hippocampus in vivo.

  7. From the test tube to the cell: exploring the folding and aggregation of a beta-clam protein.

    Science.gov (United States)

    Ignatova, Zoya; Krishnan, Beena; Bombardier, Jeffrey P; Marcelino, Anna Marie C; Hong, Jiang; Gierasch, Lila M

    2007-01-01

    A crucial challenge in present biomedical research is the elucidation of how fundamental processes like protein folding and aggregation occur in the complex environment of the cell. Many new physico-chemical factors like crowding and confinement must be considered, and immense technical hurdles must be overcome in order to explore these processes in vivo. Understanding protein misfolding and aggregation diseases and developing therapeutic strategies to these diseases demand that we gain mechanistic insight into behaviors and misbehaviors of proteins as they fold in vivo. We have developed a fluorescence approach using FlAsH labeling to study the thermodynamics of folding of a model beta-rich protein, cellular retinoic acid binding protein (CRABP) in Escherichia coli cells. The labeling approach has also enabled us to follow aggregation of a modified version of CRABP and chimeras between CRABP and huntingtin exon 1 with its glutamine repeat tract. In this article, we review our recent results using FlAsH labeling to study in-vivo folding and present new observations that hint at fundamental differences between the thermodynamics and kinetics of protein folding in vivo and in vitro.

  8. Promotion on Nucleation and Aggregation of Calcium Oxalate Crystals by Injured African Green Monkey Renal Epithelial Cells

    Institute of Scientific and Technical Information of China (English)

    张燊; 彭花; 姚秀琼; 苏泽轩; 欧阳健明

    2012-01-01

    The purpose of this work was to detect the properties of African green monkey renal epithelial cells (Vero) after oxidative injury and to study the mediation of the injured Vero on aggregation and formation of calcium oxalate crystals. This injury model was induced by 0.15 mmol/L H2O2 according to the pretest evaluation. The results suggested that H2O2 could injure Vero significantly and decrease cell viability in a time-dependent manner for exposure time of 0.5--2 h. After cell injury, the indexes connected with oxidative injury changed. The malondialdehyde (MDA) content and osteopontin (OPN) expression increased, while superoxide dismutase (SOD) level decreased. It resulted in the increase of both the amount of CaOxa crystals and the degree of crystal aggregation on the injured cells. This work indicated that injured cells promoted the formation of calcium oxalate monohydrate (COM) crystals, thus increased the risk of formation of urinary stone.

  9. Resveratrol, Acetyl-Resveratrol, and Polydatin Exhibit Antigrowth Activity against 3D Cell Aggregates of the SKOV-3 and OVCAR-8 Ovarian Cancer Cell Lines

    OpenAIRE

    Hogg, Simon J.; Kenny Chitcholtan; Wafaa Hassan; Peter H. Sykes; Ashley Garrill

    2015-01-01

    Resveratrol has aroused significant scientific interest as it has been claimed that it exhibits a spectrum of health benefits. These include effects as an anti-inflammatory and an antitumour compound. The purpose of this study was to investigate and compare any potential antigrowth effects of resveratrol and two of its derivatives, acetyl-resveratrol and polydatin, on 3D cell aggregates of the EGFR/Her-2 positive and negative ovarian cancer cell lines SKOV-3 and OVCAR-8, respectively. Results...

  10. The role of anticipated regret in escalation of commitment.

    Science.gov (United States)

    Wong, Kin Fai Ellick; Kwong, Jessica Y Y

    2007-03-01

    This research tests the general proposition that people are motivated to reduce future regret under escalation situations. This is supported by the findings that (a) escalation of commitment is stronger when the possibility of future regret about withdrawal is high than when this possibility is low (Studies 1a and 1b) and (b) escalation of commitment increases as the net anticipated regret about withdrawal increases (Studies 2a and 2b). Furthermore, the regret effects in the 4 studies were above and beyond the personal responsibility effects on escalation. This research indicates that people in escalation situations are simultaneously influenced by the emotions they expect to experience in the future (e.g., anticipated regret) and by events that have happened in the past (e.g., responsibility for the initiating previous decision).

  11. A computer-assisted 3D model for analyzing the aggregation of tumorigenic cells reveals specialized behaviors and unique cell types that facilitate aggregate coalescence.

    Directory of Open Access Journals (Sweden)

    Amanda Scherer

    Full Text Available We have developed a 4D computer-assisted reconstruction and motion analysis system, J3D-DIAS 4.1, and applied it to the reconstruction and motion analysis of tumorigenic cells in a 3D matrix. The system is unique in that it is fast, high-resolution, acquires optical sections using DIC microscopy (hence there is no associated photoxicity, and is capable of long-term 4D reconstruction. Specifically, a z-series at 5 μm increments can be acquired in less than a minute on tissue samples embedded in a 1.5 mm thick 3D Matrigel matrix. Reconstruction can be repeated at intervals as short as every minute and continued for 30 days or longer. Images are converted to mathematical representations from which quantitative parameters can be derived. Application of this system to cancer cells from established lines and fresh tumor tissue has revealed unique behaviors and cell types not present in non-tumorigenic lines. We report here that cells from tumorigenic lines and tumors undergo rapid coalescence in 3D, mediated by specific cell types that we have named "facilitators" and "probes." A third cell type, the "dervish", is capable of rapid movement through the gel and does not adhere to it. These cell types have never before been described. Our data suggest that tumorigenesis in vitro is a developmental process involving coalescence facilitated by specialized cells that culminates in large hollow spheres with complex architecture. The unique effects of select monoclonal antibodies on these processes demonstrate the usefulness of the model for analyzing the mechanisms of anti-cancer drugs.

  12. The genetic heterozygosity and fitness of tetraploid embryos and embryonic stem cells are crucial parameters influencing survival of mice derived from embryonic stem cells by tetraploid embryo aggregation.

    Science.gov (United States)

    Li, Xiangyun; Wei, Wei; Yong, Jun; Jia, Qing; Yu, Yuansong; Di, Keqian

    2005-07-01

    The aim of this paper was to determine whether the genetic background of tetraploid embryos contributed to the survival of mice derived from embryonic stem (ES) cells by tetraploid embryo complementation. Twenty-five newborns were produced by aggregation of hybrid ES cells and tetraploid embryos with different genetic backgrounds. These newborns were entirely derived from ES cells judged by microsatellite DNA (A specific sequence of DNA bases or nucleotides that contains mono, di, tri or tetra repeats) and coat colour phenotype and germline transmission. Fifteen survived to adulthood while seven died of respiratory failure. All newborns were derived from outbred or hybrid tetraploid aggregates and no newborns were from the inbreds. Our results demonstrate that the genetic heterozygosity, fitness of tetraploid embryos and fitness of ES cells are crucial parameters influencing survival of mice derived from ES cells by tetraploid embryo aggregation. In addition, this method represents a simple and efficient procedure for immediate generation of targeted mouse mutants from genetically modified ES cell clones, in contrast to the standard protocol, which involves the production of chimeras and several breeding steps.

  13. Cellulose synthase complexes act in a concerted fashion to synthesize highly aggregated cellulose in secondary cell walls of plants.

    Science.gov (United States)

    Li, Shundai; Bashline, Logan; Zheng, Yunzhen; Xin, Xiaoran; Huang, Shixin; Kong, Zhaosheng; Kim, Seong H; Cosgrove, Daniel J; Gu, Ying

    2016-10-04

    Cellulose, often touted as the most abundant biopolymer on Earth, is a critical component of the plant cell wall and is synthesized by plasma membrane-spanning cellulose synthase (CESA) enzymes, which in plants are organized into rosette-like CESA complexes (CSCs). Plants construct two types of cell walls, primary cell walls (PCWs) and secondary cell walls (SCWs), which differ in composition, structure, and purpose. Cellulose in PCWs and SCWs is chemically identical but has different physical characteristics. During PCW synthesis, multiple dispersed CSCs move along a shared linear track in opposing directions while synthesizing cellulose microfibrils with low aggregation. In contrast, during SCW synthesis, we observed swaths of densely arranged CSCs that moved in the same direction along tracks while synthesizing cellulose microfibrils that became highly aggregated. Our data support a model in which distinct spatiotemporal features of active CSCs during PCW and SCW synthesis contribute to the formation of cellulose with distinct structure and organization in PCWs and SCWs of Arabidopsis thaliana This study provides a foundation for understanding differences in the formation, structure, and organization of cellulose in PCWs and SCWs.

  14. Interactions of Pluronic nanocarriers with 2D and 3D cell cultures: Effects of PEO block length and aggregation state.

    Science.gov (United States)

    Arranja, Alexandra; Denkova, Antonia G; Morawska, Karolina; Waton, Gilles; van Vlierberghe, Sandra; Dubruel, Peter; Schosseler, François; Mendes, Eduardo

    2016-02-28

    This work reveals how the physicochemical properties of Pluronic block copolymers influence significantly their interactions with cancer cells, whether in monolayer or spheroid cultures, and how different clinical applications can be foreseen. Two-dimensional (2D) and three-dimensional (3D) cell culture models were used to investigate the interactions of Pluronic carriers with different PEO block length and aggregation state (unimers versus cross-linked micelles) in HeLa and U87 cancer cells. Stabilized micelles of Pluronic P94 or F127 were obtained by polymerization of a crosslinking agent in the micelles hydrophobic core. Nanocarriers were functionalized with a fluorescent probe for visualization, and with a chelator for radiolabeling with Indium-111 and gamma-quantification. The 2D cell models revealed that the internalization pathways and ultimate cellular localization of the Pluronic nanocarriers depended largely on both the PEO block size and aggregation state of the copolymers. The smaller P94 unimers with an average radius of 2.1nm and the shortest PEO block mass (1100gmol(-1)) displayed the highest cellular uptake and retention. 3D tumor spheroids were used to assess the penetration capacity and toxicity potential of the nanocarriers. Results showed that cross-linked F127 micelles were more efficiently delivered across the tumor spheroids, and the penetration depth depends mostly on the transcellular transport of the carriers. The Pluronic P94-based carriers with the shortest PEO block length induced spheroid toxicity, which was significantly influenced by the spheroid cellular type.

  15. Protein oxidation and aggregation in UVA-irradiated Escherichia coli cells as signs of accelerated cellular senescence.

    Science.gov (United States)

    Bosshard, Franziska; Riedel, Kathrin; Schneider, Thomas; Geiser, Carina; Bucheli, Margarete; Egli, Thomas

    2010-11-01

    Solar disinfection (SODIS) is a simple drinking water treatment method that improves microbiological water quality where other means are unavailable. It makes use of the deleterious effect of solar irradiation on pathogenic microbes and viruses. A positive impact on health has been documented in several epidemiological studies. However, the molecular mechanisms damaging cells during this simple treatment are not yet fully understood. Here we show that protein damage is crucial in the process of inactivation by sunlight. Protein damages in UVA-irradiated Escherichia coli cells have been evaluated by an immunoblot method for carbonylated proteins and an aggregation assay based on semi-quantitative proteomics. A wide spectrum of structural and enzymatic proteins within the cell is affected by carbonylation and aggregation. Vital cellular functions like the transcription and translation apparatus, transport systems, amino acid synthesis and degradation, respiration, ATP synthesis, glycolysis, the TCA cycle, chaperone functions and catalase are targeted by UVA irradiation. The protein damage pattern caused by SODIS strongly resembles the pattern caused by reactive oxygen stress. Hence, sunlight probably accelerates cellular senescence and leads to the inactivation and finally death of UVA-irradiated cells.

  16. EDTA enhances high-throughput two-dimensional bioprinting by inhibiting salt scaling and cell aggregation at the nozzle surface.

    Science.gov (United States)

    Parzel, Cheryl A; Pepper, Matthew E; Burg, Timothy; Groff, Richard E; Burg, Karen J L

    2009-06-01

    Tissue-engineering strategies may be employed in the development of in vitro breast tissue models for use in testing regimens of drug therapies and vaccines. The physical and chemical interactions that occur among cells and extracellular matrix components can also be elucidated with these models to gain an understanding of the progression of transformed epithelial cells into tumours and the ultimate metastases of tumour cells. The modified inkjet printer may be a useful tool for creating three-dimensional (3D) in vitro models, because it offers an inexpensive and high-throughput solution to microfabrication, and because the printer can be easily manipulated to produce varying tissue attributes. We hypothesized, however, that when ink is replaced with a biologically based fluid (i.e. a 'bio-ink'), specifically a serum-free cell culture medium, printer nozzle failure can result from salt scale build-up as fluid evaporates on the printhead surface. In this study, ethylene diamine tetra-acetic acid (EDTA) was used as a culture medium additive to prevent salt scaling and cell aggregation during the bioprinting process. The results showed that EDTA, at a concentration typically found in commercially available trypsin solutions (0.53 mM), prevented nozzle failure when a serum-free culture medium was printed from a nozzle at 1000 drops/s. Furthermore, increasing concentrations of EDTA appeared to mildly decrease aggregation of 4T07 cells. Cell viability studies were performed to demonstrate that addition of EDTA did not result in significant cell death. In conclusion, it is recommended that EDTA be incorporated into bio-ink solutions containing salts that could lead to nozzle failure.

  17. Mitochondrial trafficking through Rhot1 is involved in the aggregation of germinal granule components during primordial germ cell formation in Xenopus embryos.

    Science.gov (United States)

    Tada, Haru; Taira, Yuya; Morichika, Keisuke; Kinoshita, Tsutomu

    2016-10-01

    In many animals, the germ plasm is sufficient and necessary for primordial germ cell (PGC) formation. It contains germinal granules and abundant mitochondria (germline-Mt). However, the role of germline-Mt in germ cell formation remains poorly understood. In Xenopus, the germ plasm is distributed as many small islands at the vegetal pole, which gradually aggregates to form a single large mass in each of the four vegetal pole cells at the early blastula stage. Polymerized microtubules and the adapter protein kinesin are required for the aggregation of germ plasm. However, it remains unknown whether germline-Mt trafficking is important for the cytoplasmic transport of germinal granules during germ plasm aggregation. In this study, we focused on the mitochondrial small GTPase protein Rhot1 to inhibit mitochondrial trafficking during the germ plasm aggregation. Expression of Rhot1ΔC, which lacks the C-terminal mitochondrial transmembrane domain, inhibited the aggregation of germline-Mt during early development. In Rhot1-inhibited embryos, germinal granule components did not aggregate during cleavage stages, which reduced the number of PGCs on the genital ridge at tail-bud stage. These results suggest that mitochondrial trafficking is involved in the aggregation of germinal granule components, which are essential for the formation of PGCs.

  18. Effect of the surfactant tween 80 on the detachment and dispersal of Salmonella enterica serovar Thompson single cells and aggregates from cilantro leaves as revealed by image analysis.

    Science.gov (United States)

    Brandl, Maria T; Huynh, Steven

    2014-08-01

    Salmonella enterica has the ability to form biofilms and large aggregates on produce surfaces, including on cilantro leaves. Aggregates of S. enterica serovar Thompson that remained attached to cilantro leaves after rigorous washing and that were present free or bound to dislodged leaf tissue in the wash suspension were observed by confocal microscopy. Measurement of S. Thompson population sizes in the leaf washes by plate counts failed to show an effect of 0.05% Tween 80 on the removal of the pathogen from cilantro leaves 2 and 6 days after inoculation. On the contrary, digital image analysis of micrographs of single cells and aggregates of green fluorescent protein (GFP)-S. Thompson present in cilantro leaf washes revealed that single cells represented 13.7% of the cell assemblages in leaf washes containing Tween 80, versus 9.3% in those without the surfactant. Moreover, Tween 80 decreased the percentage of the total S. Thompson cell population located in aggregates equal to or larger than 64 cells from 9.8% to 4.4% (P Tween 80 showed that the surfactant promoted the dispersal of cells from large aggregates into smaller ones and into single cells (P < 0.05). Our study underlines the importance of investigating bacterial behavior at the scale of single cells in order to uncover trends undetectable at the population level by bacterial plate counts. Such an approach may provide valuable information to devise strategies aimed at enhancing the efficacy of produce sanitization treatments.

  19. Method for Producing Non-Neoplastic, Three Dimensional, Mammalian Tissue and Cell Aggregates Under Microgravity Culture Conditions and the Products Produced Therefrom

    Science.gov (United States)

    Goodwin, Thomas J. (Inventor); Wolf, David A. (Inventor); Spaulding, Glenn F. (Inventor); Prewett, Tracey L. (Inventor)

    1996-01-01

    Normal mammalian tissue and the culturing process has been developed for the three groups of organ, structural, and blood tissue. The cells are grown in vitro under microgravity culture conditions and form three dimensional cells aggregates with normal cell function. The microgravity culture conditions may be microgravity or simulated microgravity created in a horizontal rotating wall culture vessel.

  20. In vitro generation of three-dimensional substrate-adherent embryonic stem cell-derived neural aggregates for application in animal models of neurological disorders.

    Science.gov (United States)

    Hargus, Gunnar; Cui, Yi-Fang; Dihné, Marcel; Bernreuther, Christian; Schachner, Melitta

    2012-05-01

    In vitro-differentiated embryonic stem (ES) cells comprise a useful source for cell replacement therapy, but the efficiency and safety of a translational approach are highly dependent on optimized protocols for directed differentiation of ES cells into the desired cell types in vitro. Furthermore, the transplantation of three-dimensional ES cell-derived structures instead of a single-cell suspension may improve graft survival and function by providing a beneficial microenvironment for implanted cells. To this end, we have developed a new method to efficiently differentiate mouse ES cells into neural aggregates that consist predominantly (>90%) of postmitotic neurons, neural progenitor cells, and radial glia-like cells. When transplanted into the excitotoxically lesioned striatum of adult mice, these substrate-adherent embryonic stem cell-derived neural aggregates (SENAs) showed significant advantages over transplanted single-cell suspensions of ES cell-derived neural cells, including improved survival of GABAergic neurons, increased cell migration, and significantly decreased risk of teratoma formation. Furthermore, SENAs mediated functional improvement after transplantation into animal models of Parkinson's disease and spinal cord injury. This unit describes in detail how SENAs are efficiently derived from mouse ES cells in vitro and how SENAs are isolated for transplantation. Furthermore, methods are presented for successful implantation of SENAs into animal models of Huntington's disease, Parkinson's disease, and spinal cord injury to study the effects of stem cell-derived neural aggregates in a disease context in vivo.

  1. Disulfide scrambling in superoxide dismutase 1 reduces its cytotoxic effect in cultured cells and promotes protein aggregation.

    Directory of Open Access Journals (Sweden)

    Lina Leinartaitė

    Full Text Available Mutations in the gene coding for superoxide dismutase 1 (SOD1 are associated with familiar forms of the neurodegenerative disease amyotrophic lateral sclerosis (ALS. These mutations are believed to result in a "gain of toxic function", leading to neuronal degeneration. The exact mechanism is still unknown, but misfolding/aggregation events are generally acknowledged as important pathological events in this process. Recently, we observed that demetallated apoSOD1, with cysteine 6 and 111 substituted for alanine, is toxic to cultured neuroblastoma cells. This toxicity depended on an intact, high affinity Zn(2+ site. It was therefor contradictory to discover that wild-type apoSOD1 was not toxic, despite of its high affinity for Zn(2+. This inconsistency was hypothesized to originate from erroneous disulfide formation involving C6 and C111. Using high resolution non-reducing SDS-PAGE, we have in this study demonstrated that the inability of wild-type apoSOD1 to cause cell death stems from formation of non-native intra-molecular disulfides. Moreover, monomeric apoSOD1 variants capable of such disulfide scrambling aggregated into ThT positive oligomers under physiological conditions without agitation. The oligomers were stabilized by inter-molecular disulfides and morphologically resembled what has in other neurodegenerative diseases been termed protofibrils. Disulfide scrambling thus appears to be an important event for misfolding and aggregation of SOD1, but may also be significant for protein function involving cysteines, e.g. mitochondrial import and copper loading.

  2. Three cyanobacteriochromes work together to form a light color-sensitive input system for c-di-GMP signaling of cell aggregation.

    Science.gov (United States)

    Enomoto, Gen; Ni-Ni-Win; Narikawa, Rei; Ikeuchi, Masahiko

    2015-06-30

    Cyanobacteriochromes (CBCRs) are cyanobacterial photoreceptors that have diverse spectral properties and domain compositions. Although large numbers of CBCR genes exist in cyanobacterial genomes, no studies have assessed whether multiple CBCRs work together. We recently showed that the diguanylate cyclase (DGC) activity of the CBCR SesA from Thermosynechococcus elongatus is activated by blue-light irradiation and that, when irradiated, SesA, via its product cyclic dimeric GMP (c-di-GMP), induces aggregation of Thermosynechococcus vulcanus cells at a temperature that is suboptimum for single-cell viability. For this report, we first characterize the photobiochemical properties of two additional CBCRs, SesB and SesC. Blue/teal light-responsive SesB has only c-di-GMP phosphodiesterase (PDE) activity, which is up-regulated by teal light and GTP. Blue/green light-responsive SesC has DGC and PDE activities. Its DGC activity is enhanced by blue light, whereas its PDE activity is enhanced by green light. A ΔsesB mutant cannot suppress cell aggregation under teal-green light. A ΔsesC mutant shows a less sensitive cell-aggregation response to ambient light. ΔsesA/ΔsesB/ΔsesC shows partial cell aggregation, which is accompanied by the loss of color dependency, implying that a nonphotoresponsive DGC(s) producing c-di-GMP can also induce the aggregation. The results suggest that SesB enhances the light color dependency of cell aggregation by degrading c-di-GMP, is particularly effective under teal light, and, therefore, seems to counteract the induction of cell aggregation by SesA. In addition, SesC seems to improve signaling specificity as an auxiliary backup to SesA/SesB activities. The coordinated action of these three CBCRs highlights why so many different CBCRs exist.

  3. Dissipative particle dynamics simulations of deformation and aggregation of healthy and diseased red blood cells in a tube flow

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Ting; Phan-Thien, Nhan, E-mail: Nhan@nus.edu.sg; Khoo, Boo Cheong; Lim, Chwee Teck [Department of Mechanical Engineering, National University of Singapore, Singapore 119260 (Singapore)

    2014-11-15

    In this paper, we report simulation results assessing the deformation and aggregation of mixed healthy and malaria-infected red blood cells (RBCs) in a tube flow. A three dimensional particle model based on Dissipative Particle Dynamics (DPD) is developed to predict the tube flow containing interacting cells. The cells are also modelled by DPD, with a Morse potential to characterize the cell-cell interaction. As validation tests, a single RBC in a tube flow and two RBCs in a static flow are simulated to examine the cell deformation and intercellular interaction, respectively. The study of two cells, one healthy and the other malaria-infected RBCs in a tube flow demonstrates that the malaria-infected RBC (in the leading position along flow direction) has different effects on the healthy RBC (in the trailing position) at the different stage of parasite development or at the different capillary number. With parasitic development, the malaria-infected RBC gradually loses its deformability, and in turn the corresponding trailing healthy RBC also deforms less due to the intercellular interaction. With increasing capillary number, both the healthy and malaria-infected RBCs are likely to undergo an axisymmetric motion. The minimum intercellular distance becomes small enough so that rouleaux is easily formed, i.e., the healthy and malaria-infected RBCs are difficultly disaggregated.

  4. In vitro cytotoxicity of fluorescent silica nanoparticles hybridized with aggregation-induced emission luminogens for living cell imaging.

    Science.gov (United States)

    Xia, Yun; Li, Min; Peng, Tao; Zhang, Weijie; Xiong, Jun; Hu, Qinggang; Song, Zifang; Zheng, Qichang

    2013-01-07

    Fluorescent silica nanoparticles (FSNPs) can provide high-intensity and photostable fluorescent signals as a probe for biomedical analysis. In this study, FSNPs hybridized with aggregation-induced emission (AIE) luminogens (namely FSNP-SD) were successfully fabricated by a surfactant-free sol-gel method. The FSNP-SD were spherical, monodisperse and uniform in size, with an average diameter of approximately 100 nm, and emitted strong fluorescence at the peak of 490 nm. The FSNP-SD selectively stained the cytoplasmic regions and were distributed in the cytoplasm. Moreover, they can stay inside cells, enabling the tacking of cells over a long period of time. The intracellular vesicles and multinucleated cells were increase gradually with the rise of FSNP-SD concentration. Both cell viability and survival only lost less than 20% when the cells were exposed to the high concentration of 100 μg/mL FSNP-SD. Additionally, the cell apoptosis and intracellular ROS assay indicated that FSNP-SD had no significant toxic effects at the maximum working concentration of 80 μg/mL. This study demonstrated that the FSNP-SD are promising biocompatible fluorescent probes for living cell imaging.

  5. In Vitro Cytotoxicity of Fluorescent Silica Nanoparticles Hybridized with Aggregation-Induced Emission Luminogens for Living Cell Imaging

    Directory of Open Access Journals (Sweden)

    Yun Xia

    2013-01-01

    Full Text Available Fluorescent silica nanoparticles (FSNPs can provide high-intensity and photostable fluorescent signals as a probe for biomedical analysis. In this study, FSNPs hybridized with aggregation-induced emission (AIE luminogens (namely FSNP-SD were successfully fabricated by a surfactant-free sol-gel method. The FSNP-SD were spherical, monodisperse and uniform in size, with an average diameter of approximately 100 nm, and emitted strong fluorescence at the peak of 490 nm. The FSNP-SD selectively stained the cytoplasmic regions and were distributed in the cytoplasm. Moreover, they can stay inside cells, enabling the tacking of cells over a long period of time. The intracellular vesicles and multinucleated cells were increase gradually with the rise of FSNP-SD concentration. Both cell viability and survival only lost less than 20% when the cells were exposed to the high concentration of 100 μg/mL FSNP-SD. Additionally, the cell apoptosis and intracellular ROS assay indicated that FSNP-SD had no significant toxic effects at the maximum working concentration of 80 μg/mL. This study demonstrated that the FSNP-SD are promising biocompatible fluorescent probes for living cell imaging.

  6. A New SDH-Based ATM Network Survivability Escalation Mechanism

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper investigates survivability escalation strategies in multi-layers transport networks such as ATM/SDH/WDM networks, and presents oriented-failures and oriented-traffic escalation mechanisms. Furthermore, We present a new survivability Escalation strategy for SDH-Based ATM transport networks, which addresses difficult problem for resources sharing pool(RSP) among different layers restoration mechanisms. In this paper, we also present integer programming (IP) model for the resources sharing pool (RSP) design problem and the node simulation model for escalation Node. The simulation results show that the proposed ESP is very efficient. The proposed model can be easily extended for other types of multi-layer networks, such as WDM-based ATM networks or WDM-based SDH networks.

  7. Abrogation of E-cadherin-mediated cellular aggregation allows proliferation of pluripotent mouse embryonic stem cells in shake flask bioreactors.

    Directory of Open Access Journals (Sweden)

    Lisa Mohamet

    Full Text Available BACKGROUND: A fundamental requirement for the exploitation of embryonic stem (ES cells in regenerative medicine is the ability to reproducibly derive sufficient numbers of cells of a consistent quality in a cost-effective manner. However, undifferentiated ES cells are not ideally suited to suspension culture due to the formation of cellular aggregates, ultimately limiting scalability. Significant advances have been made in recent years in the culture of ES cells, including automated adherent culture and suspension microcarrier or embryoid body bioreactor culture. However, each of these methods exhibits specific disadvantages, such as high cost, additional downstream processes or reduced cell doubling times. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that abrogation of the cell surface protein E-cadherin, using either gene knockout (Ecad-/- or the neutralising antibody DECMA-1 (EcadAb, allows culture of mouse ES cells as a near-single cell suspension in scalable shake flask culture over prolonged periods without additional media supplements. Both Ecad-/- and EcadAb ES cells exhibited adaptation phases in suspension culture, with optimal doubling times of 7.3 h±0.9 and 15.6 h±4.7 respectively and mean-fold increase in viable cell number of 95.1±2.0 and 16±0.9-fold over 48 h. EcadAb ES cells propagated as a dispersed cell suspension for 15 d maintained expression of pluripotent markers, exhibited a normal karyotype and high viability. Subsequent differentiation of EcadAb ES cells resulted in expression of transcripts and proteins associated with the three primary germ layers. CONCLUSIONS/SIGNIFICANCE: This is the first demonstration of the culture of pluripotent ES cells as a near-single cell suspension in a manual fed-batch shake flask bioreactor and represents a significant improvement on current ES cell culture techniques. Whilst this proof-of-principle method would be useful for the culture of human ES and iPS cells, further steps are

  8. Soviet declaratory policy regarding the controllability of escalation

    Energy Technology Data Exchange (ETDEWEB)

    Prewitt, J.L.

    1991-01-01

    Three variables were examined for their affect on Soviet views regarding the controllability of escalation. The first was bureaucratic affiliation. It was hypothesized that individuals affiliated with groups which directly controlled weapons would be more likely to support the controllability of escalation than those who were members of groups which did not control weapons. This hypothesis could not be rejected. The second variable was a commentator's rank. It was hypothesized that rank would act in two ways: (1) ideas regarding controlled escalation would appear at lower ranks first; and (2) unique views would be produced by specialized ranks within groups. The rank hypothesis could not be rejected. Certain escalation themes appeared to be presented first by military and civilian writers before being presented by the political leadership. The third variable, image of the West, did not appear to function as theorized. It was hypothesized that hard images of the West would be associated with the rejection of controlled escalation, whereas soft images would be associated with positions suggesting that escalation was controlled through joint US-Soviet cooperation.

  9. Serum replacement with albumin-associated lipids prevents excess aggregation and enhances growth of induced pluripotent stem cells in suspension culture.

    Science.gov (United States)

    Horiguchi, Ikki; Sakai, Yasuyuki

    2016-07-08

    Suspension culture systems are currently under investigation for the mass production of pluripotent stem (PS) cells for tissue engineering; however, the control of cell aggregation in suspension culture remains challenging. Existing methods to control aggregation such as microwell culture are difficult to scale up. To address this issue, in this study a novel method that incorporates the addition of KnockOut Serum Replacement (KSR) to the PS cell culture medium was described. The method regulated cellular aggregation and significantly improved cell growth (a 2- to 10-fold increase) without any influence on pluripotency. In addition, albumin-associated lipids as the major working ingredient of KSR responsible for this inhibition of aggregation were identified. This is one of the simplest methods described to date to control aggregation and requires only chemically synthesizable reagents. Thus, this method has the potential to simplify the mass production process of PS cells and thus lower their cost. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1009-1016, 2016.

  10. Phenotypic switch in blood: effects of pro-inflammatory cytokines on breast cancer cell aggregation and adhesion.

    Directory of Open Access Journals (Sweden)

    Yue Geng

    Full Text Available Hematogeneous metastasis can occur via a cascade of circulating tumor cell adhesion events to the endothelial lining of the vasculature, i.e. the metastatic cascade. Interestingly, the pro-inflammatory cytokines IL-6 and TNF-α, which play an important role in potentiating the inflammatory cascade, are significantly elevated in metastatic breast cancer (BCa patients. Despite their high metastatic potential, human breast carcinoma cells MDA-MB-231 lack interactions with E-selectin functionalized surfaces under physiological shear stresses. We hypothesized that human plasma, 3-D tumor spheroid culture, and cytokine-supplemented culture media could induce a phenotypic switch that allows BCa cells to interact with E-selectin coated surfaces under physiological flow. Flow cytometry, immunofluorescence imaging, and flow-based cell adhesion assay were utilized to investigate the phenotypic changes of MDA-MB-231 cells with various treatments. Our results indicate that plasma, IL-6, and TNF-α promote breast cancer cell growth as aggregates and induce adhesive recruitment of BCa cells on E-selectin coated surfaces under flow. 3-D tumor spheroid culture exhibits the most significant increases in the interactions between BCa and E-selectin coated surfaces by upregulating CD44V4 and sLe(x expression. Furthermore, we show that IL-6 and TNF-α concentrations in blood may regulate the recruitment of BCa cells to the inflamed endothelium. Finally, we propose a mechanism that could explain the invasiveness of 'triple-negative' breast cancer cell line MDA-MB-231 via a positive feedback loop of IL-6 secretion and maintenance. Taken together, our results suggest that therapeutic approaches targeting cytokine receptors and adhesion molecules on cancer cells may potentially reduce metastatic load and improve current cancer treatments.

  11. In vivo venous assessment of red blood cell aggregate sizes in diabetic patients with a quantitative cellular ultrasound imaging method: proof of concept.

    Directory of Open Access Journals (Sweden)

    Julien Tripette

    Full Text Available Diabetic patients present higher level of red blood cell (RBC aggregation contributing to the development of vascular complications. While it has been suggested that this hematology/rheology parameter could bring additional prognostic information for the management of those patients, RBC aggregation screening is not included as a clinical practice. Most medical centers are not equipped to measure properly this parameter, although sedimentation tests can bring some indication. Here, we aimed at evaluating the feasibility of using ultrasound to assess in-vivo hyper-aggregation in type 2 diabetic patients.Seventeen diabetic patients and 15 control subjects underwent ultrasound measurements of RBC aggregation in both cephalic and great saphenous veins. Non-invasive in-vivo ultrasound measurements were performed using a newly developed cellular imaging technique, the structure factor size and attenuation estimator (SFSAE. Comparisons with an ex-vivo gold standard rheometry technique were done, along with measurements of pro-aggregating plasma molecule concentrations.In-vivo RBC aggregation was significantly higher in diabetic patients compared with controls for cephalic vein measurements, while a trend (p = 0.055 was noticed in the great saphenous vein. SFSAE measurements were correlated with gold standard in-vitro measures, fibrinogen and C-reactive protein plasma concentrations.RBC aggregation can be measured in-vivo in diabetic patients using ultrasound. Prospective studies are needed to determine whether the SFSAE method could help clinicians in the early management of vascular complications in this patient population.

  12. P2Y2 nucleotide receptor activation enhances the aggregation and self-organization of dispersed salivary epithelial cells.

    Science.gov (United States)

    El-Sayed, Farid G; Camden, Jean M; Woods, Lucas T; Khalafalla, Mahmoud G; Petris, Michael J; Erb, Laurie; Weisman, Gary A

    2014-07-01

    Hyposalivation resulting from salivary gland dysfunction leads to poor oral health and greatly reduces the quality of life of patients. Current treatments for hyposalivation are limited. However, regenerative medicine to replace dysfunctional salivary glands represents a revolutionary approach. The ability of dispersed salivary epithelial cells or salivary gland-derived progenitor cells to self-organize into acinar-like spheres or branching structures that mimic the native tissue holds promise for cell-based reconstitution of a functional salivary gland. However, the mechanisms involved in salivary epithelial cell aggregation and tissue reconstitution are not fully understood. This study investigated the role of the P2Y2 nucleotide receptor (P2Y2R), a G protein-coupled receptor that is upregulated following salivary gland damage and disease, in salivary gland reconstitution. In vitro results with the rat parotid acinar Par-C10 cell line indicate that P2Y2R activation with the selective agonist UTP enhances the self-organization of dispersed salivary epithelial cells into acinar-like spheres. Other results indicate that the P2Y2R-mediated response is dependent on epidermal growth factor receptor activation via the metalloproteases ADAM10/ADAM17 or the α5β1 integrin/Cdc42 signaling pathway, which leads to activation of the MAPKs JNK and ERK1/2. Ex vivo data using primary submandibular gland cells from wild-type and P2Y2R(-/-) mice confirmed that UTP-induced migratory responses required for acinar cell self-organization are mediated by the P2Y2R. Overall, this study suggests that the P2Y2R is a promising target for salivary gland reconstitution and identifies the involvement of two novel components of the P2Y2R signaling cascade in salivary epithelial cells, the α5β1 integrin and the Rho GTPase Cdc42.

  13. SIRT1 modulates aggregation and toxicity through deacetylation of the androgen receptor in cell models of SBMA.

    Science.gov (United States)

    Montie, Heather L; Pestell, Richard G; Merry, Diane E

    2011-11-30

    Posttranslational protein modifications can play a major role in disease pathogenesis; phosphorylation, sumoylation, and acetylation modulate the toxicity of a variety of proteotoxic proteins. The androgen receptor (AR) is substantially modified, in response to hormone binding, by phosphorylation, sumoylation, and acetylation; these modifications might thus contribute to DHT-dependent polyglutamine (polyQ)-expanded AR proteotoxicity in spinal and bulbar muscular atrophy (SBMA). SIRT1, a nuclear protein and deacetylase of the AR, is neuroprotective in many neurodegenerative disease models. Our studies reveal that SIRT1 also offers protection against polyQ-expanded AR by deacetylating the AR at lysines 630/632/633. This finding suggested that nuclear AR acetylation plays a role in the aberrant metabolism and toxicity of polyQ-expanded AR. Subsequent studies revealed that the polyQ-expanded AR is hyperacetylated and that pharmacologic reduction of acetylation reduces mutant AR aggregation. Moreover, genetic mutation to inhibit polyQ-expanded AR acetylation of lysines 630/632/633 substantially decreased its aggregation and completely abrogated its toxicity in cell lines and motor neurons. Our studies also reveal one means by which the AR acetylation state likely modifies polyQ-expanded AR metabolism and toxicity, through its effect on DHT-dependent AR stabilization. Overall, our findings reveal a neuroprotective function of SIRT1 that operates through its deacetylation of polyQ-expanded AR and highlight the potential of both SIRT1 and AR acetylation as powerful therapeutic targets in SBMA.

  14. Estimation of size of red blood cell aggregates using backscattering property of high-frequency ultrasound: In vivo evaluation

    Science.gov (United States)

    Kurokawa, Yusaku; Taki, Hirofumi; Yashiro, Satoshi; Nagasawa, Kan; Ishigaki, Yasushi; Kanai, Hiroshi

    2016-07-01

    We propose a method for assessment of the degree of red blood cell (RBC) aggregation using the backscattering property of high-frequency ultrasound. In this method, the scattering property of RBCs is extracted from the power spectrum of RBC echoes normalized by that from the posterior wall of a vein. In an experimental study using a phantom, employing the proposed method, the sizes of microspheres 5 and 20 µm in diameter were estimated to have mean values of 4.7 and 17.3 µm and standard deviations of 1.9 and 1.4 µm, respectively. In an in vivo experimental study, we compared the results between three healthy subjects and four diabetic patients. The average estimated scatterer diameters in healthy subjects at rest and during avascularization were 7 and 28 µm, respectively. In contrast, those in diabetic patients receiving both antithrombotic therapy and insulin therapy were 11 and 46 µm, respectively. These results show that the proposed method has high potential for clinical application to assess RBC aggregation, which may be related to the progress of diabetes.

  15. Identification of a small, naked virus in tumor-like aggregates in cell lines derived from a green turtle, Chelonia mydas, with fibropapillomas

    Science.gov (United States)

    Lu, Y.; Aguirre, A.A.; Work, T.M.; Balazs, G.H.; Nerurkar, V.R.; Yanagihara, R.

    2000-01-01

    Serial cultivation of cell lines derived from lung, testis, periorbital and tumor tissues of a green turtle (Chelonia mydas) with fibropapillomas resulted in the in vitro formation of tumor-like cell aggregates, ranging in size from 0.5 to 2.0 mm in diameter. Successful induction of tumor-like aggregates was achieved in a cell line derived from lung tissue of healthy green turtles, following inoculation with cell-free media from these tumor-bearing cell lines, suggesting the presence of a transmissible agent. Thin-section electron microscopy of the cell aggregates revealed massive collagen deposits and intranuclear naked viral particles, measuring 50??5 nm in diameter. These findings, together with the morphological similarity between these tumor-like cell aggregates and the naturally occurring tumor, suggest a possible association between this novel virus and the disease. Further characterization of this small naked virus will clarify its role in etiology of green turtle fibropapilloma, a life-threatening disease of this endangered marine species. Copyright (C) 2000 Elsevier Science B.V.

  16. Aggregation of human recombinant monoclonal antibodies influences the capacity of dendritic cells to stimulate adaptive T-cell responses in vitro.

    Science.gov (United States)

    Rombach-Riegraf, Verena; Karle, Anette C; Wolf, Babette; Sordé, Laetitia; Koepke, Stephan; Gottlieb, Sascha; Krieg, Jennifer; Djidja, Marie-Claude; Baban, Aida; Spindeldreher, Sebastian; Koulov, Atanas V; Kiessling, Andrea

    2014-01-01

    Subvisible proteinaceous particles which are present in all therapeutic protein formulations are in the focus of intense discussions between health authorities, academics and biopharmaceutical companies in the context of concerns that such particles could promote unwanted immunogenicity via anti-drug antibody formation. In order to provide further understanding of the subject, this study closely examines the specific biological effects proteinaceous particles may exert on dendritic cells (DCs) as the most efficient antigen-presenting cell population crucial for the initiation of the adaptive immune response. Two different model IgG antibodies were subjected to three different types of exaggerated physical stress to generate subvisible particles in far greater concentrations than the ones typical for the currently marketed biotherapeutical antibodies. The aggregated samples were used in in vitro biological assays in order to interrogate the early DC-driven events that initiate CD4 T-cell dependent humoral adaptive immune responses--peptide presentation capacity and co-stimulatory activity of DCs. Most importantly, antigen presentation was addressed with a unique approach called MHC-associated Peptide Proteomics (MAPPs), which allows for identifying the sequences of HLA-DR associated peptides directly from human dendritic cells. The experiments demonstrated that highly aggregated solutions of two model mAbs generated under controlled conditions can induce activation of human monocyte-derived DCs as indicated by upregulation of typical maturation markers including co-stimulatory molecules necessary for CD4 T-cell activation. Additional data suggest that highly aggregated proteins could induce in vitro T-cell responses. Intriguingly, strong aggregation-mediated changes in the pattern and quantity of antigen-derived HLA-DR associated peptides presented on DCs were observed, indicating a change in protein processing and presentation. Increasing the amounts of subvisible

  17. Escalation and De-escalation of Therapy in COPD: Myths, Realities and Perspectives.

    Science.gov (United States)

    Cazzola, Mario; Rogliani, Paola; Matera, Maria Gabriella

    2015-09-01

    Chronic obstructive pulmonary disease (COPD) guidelines and strategies suggest escalating treatment, mainly depending on the severity of airflow obstruction. However, some de-escalation of therapy in COPD would be appropriate, although we still do not know when we should switch, step-up or step-down treatments in our patients. Unfortunately, trials comparing different strategies of step-up and step-down treatment (e.g. treatment initiation with one single agent and then further step-up if symptoms are not controlled versus initial use of double or triple therapy, possibly with lower doses of the individual components, or the role of N-acetylcysteine in combination therapy for a step-down approach) are still lacking. In general, there is a large and often inappropriate use of the inhaled corticosteroid (ICS)/long-acting β2-agonist (LABA) combination. However, the withdrawal of the ICS in COPD patients at low risk of exacerbation can be safe, provided that patients are under regular treatment with long-acting bronchodilators. Maximising the treatment in patients with a degree of clinical instability by including an ICS in the therapeutic regimen is useful to control the disease, but may not be needed during periods of clinical stability. In patients with severe but stable COPD, the withdrawal of the ICS from triple therapy [LABA + long-acting muscarinic antagonist (LAMA) + ICS] is possible, but not when the patient has been hospitalised for an acute exacerbation of COPD. We must still establish how long we should wait before withdrawing the ICS. It is still unclear whether the same is true when only the LABA or the LAMA is withdrawn while continuing treatment with the other bronchodilator and the ICS. In any case, we strongly believe that it is always better to avoid a therapeutic step-up progression when it is not needed rather than being forced subsequently into a step-down approach in which the outcome is always unpredictable.

  18. Adenylyl cyclase localization to the uropod of aggregating Dictyostelium cells requires RacC

    Science.gov (United States)

    Wang, C.; Jung, D.; Cao, Z.; Chung, C. Y.

    2015-01-01

    The localization of adenylyl cyclase A (ACA) to uropod of cells is required for the stream formation during Dictyostelium development. RacC is a Dictyostelium orthologue of Cdc42. We identified a streaming defect of racC− cells as they are clearly less polarized and form smaller and fragmented streams. ACA-YFP is mainly associated with intracellular vesicular structures, but not with the plasma membrane in racC− cells. racC− cells have a slightly higher number of vesicles than Ax3 cells, suggesting that the defect of ACA trafficking is not simply due to the lack of vesicle formation. While the ACA-YFP vesicles traveled with an average velocity of 9.1 µm/min in Ax3 cells, a slow and diffusional movement without direction with an average velocity of 4 µm/min was maintained in racC− cells. Images acquired by using total internal reflection fluorescence (TIRF) microscopy and fluorescence recovery after photobleaching (FRAP) analysis revealed that a significantly decreased number of ACA-YFP vesicles appeared near the cell membrane, indicating a defect in ACA-YFP vesicle trafficking. These results suggest an important role of RacC in the rapid and directional movements of ACA vesicles on microtubules to the plasma membrane, especially to the back of polarized cell. PMID:26315268

  19. Abiotic factors in colony formation: effects of nutrition and light on extracellular polysaccharide production and cell aggregates of Microcystis aeruginosa

    Science.gov (United States)

    Yang, Zhen; Kong, Fanxiang

    2013-07-01

    Colony morphology is important for Microcystis to sustain a competitive advantage in eutrophic lakes. The mechanism of colony formation in Microcystis is currently unclear. Extracellular polysaccharide (EPS) has been reported to play an important role in cell aggregate formation of some phytoplankton. Microcystis aeruginosa was cultivated under varied abiotic conditions, including different nutrient, light, and temperature conditions, to investigate their effects on EPS production and morphological change. The results show that nutrient concentration and light intensity have great effects on EPS productionin M. aeruginosa. There was a considerable increase in EPS production after M. aeruginosa was cultivated in adjusted culture conditions similar to those present in the field (28.9 mg C/L, 1.98 mg N/L, 0.65 mg P/L, light intensity: 100 μmol/(m2 · s)). These results indicate that abiotic factors might be one of the triggers for colony formation in Microcystis.

  20. Mucin biopolymers prevent bacterial aggregation by retaining cells in the free-swimming state

    Science.gov (United States)

    Caldara, Marina; Friedlander, Ronn S.; Kavanaugh, Nicole L.; Aizenberg, Joanna; Foster, Kevin R.; Ribbeck, Katharina

    2013-01-01

    Summary Many species of bacteria form surface-attached communities known as biofilms. Surrounded in secreted polymers, these aggregates are difficult to both prevent and eradicate, posing problems for medicine and industry [1, 2]. Humans play host to hundreds of trillions of microbes that live adjacent to our epithelia and we are typically able to prevent harmful colonization. Mucus, the hydrogel overlying all wet epithelia in the body, can prevent bacterial contact with the underlying tissue. The digestive tract, for example, is lined by a firmly adherent mucus layer that is typically devoid of bacteria, followed by a second, loosely adherent layer that contains numerous bacteria [3]. Here, we investigate mucus's role as a principle arena for host-microbe interactions. Using defined in vitro assays, we found that mucin biopolymers, the main functional constituents of mucus, promote the motility of planktonic bacteria, and prevent their adhesion to underlying surfaces. The deletion of motility genes, however, allows Pseudomonas aeruginosa to overcome the dispersive effects of mucus and form suspended antibiotic-resistant flocs, which mirror the clustered morphology of immotile natural isolates found in the cystic fibrosis lung mucus [4, 5]. Mucus may offer new strategies to target bacterial virulence, such as the design of anti-biofilm coatings for implants. PMID:23142047

  1. Fate of bone marrow mesenchymal stem cells following the allogeneic transplantation of cartilaginous aggregates into osteochondral defects of rabbits.

    Science.gov (United States)

    Yoshioka, Tomokazu; Mishima, Hajime; Kaul, Zeenia; Ohyabu, Yoshimi; Sakai, Shinsuke; Ochiai, Naoyuki; Kaul, Sunil C; Wadhwa, Renu; Uemura, Toshimasa

    2011-06-01

    The purpose of this study was to track mesenchymal stem cells (MSCs) labelled with internalizing quantum dots (i-QDs) in the reparative tissues, following the allogeneic transplantation of three-dimensional (3D) cartilaginous aggregates into the osteochondral defects of rabbits. QDs were conjugated with a unique internalizing antibody against a heat shock protein-70 (hsp70) family stress chaperone, mortalin, which is upregulated and expressed on the surface of dividing cells. The i-QDs were added to the culture medium for 24 h. Scaffold-free cartilaginous aggregates formed from i-QD-labelled MSCs (i-MSCs), using a 3D culture system with chondrogenic supplements for 1 week, were transplanted into osteochondral defects of rabbits. At 4, 8 and 26 weeks after the transplantation, the reparative tissues were evaluated macroscopically, histologically and fluoroscopically. At as early as 4 weeks, the defects were covered with a white tissue resembling articular cartilage. In histological appearance, the reparative tissues resembled hyaline cartilage on safranin-O staining throughout the 26 weeks. In the deeper portion, subchondral bone and bone marrow were well remodelled. On fluoroscopic evaluation, QDs were tracked mainly in bone marrow stromata, with some signals detected in cartilage and the subchondral bone layer. We showed that the labelling of rabbit MSCs with anti-mortalin antibody-conjugated i-QDs is a tolerable procedure and provides a stable fluorescence signal during the cartilage repair process for up to 26 weeks after transplantation. The results suggest that i-MSCs did not inhibit, and indeed contributed to, the regeneration of osteochondral defects.

  2. Nicotine promotes Streptococcus mutans extracellular polysaccharide synthesis, cell aggregation and overall lactate dehydrogenase activity.

    Science.gov (United States)

    Huang, R; Li, M; Gregory, R L

    2015-08-01

    Several epidemiology studies have reported a positive relationship between smoking and dental caries. Nicotine, an alkaloid component of tobacco, has been demonstrated to stimulate biofilm formation and metabolic activity of Streptococcus mutans, one of the most important pathogens of dental caries. The first aim of the present study was to explore the possible mechanisms leading to increased biofilm by nicotine treatment from three aspects, extracellular polysaccharides (EPS) synthesis, glucosyltransferase (Gtf) synthesis and glucan-binding protein (Gbp) synthesis at the mRNA and protein levels. The second aim was to investigate how nicotine affects S. mutans virulence, particular in lactate dehydrogenase (LDH) activity. Confocal laser scanning microscopy results demonstrated that both biofilm bacterial cell numbers and EPS were increased by nicotine. Gtf and GbpA protein expression of S. mutans planktonic cells were upregulated while GbpB protein expression of biofilm cells were downregulated by nicotine. The mRNA expression trends of those genes were mostly consistent with results on protein level but not statistically significant, and gtfD and gbpD of biofilm cells were inhibited. Nicotine was not directly involved in S. mutans LDH activity. However, since it increases the total number of bacterial cells in biofilm, the overall LDH activity of S. mutans biofilm is increased. In conclusion, nicotine stimulates S. mutans planktonic cell Gtf and Gbp expression. This leads to more planktonic cells attaching to the dental biofilm. Increased cell numbers within biofilm results in higher overall LDH activity. This contributes to caries development in smokers.

  3. TTYH2, a human homologue of the Drosophila melanogaster gene tweety, is up-regulated in colon carcinoma and involved in cell proliferation and cell aggregation

    Institute of Scientific and Technical Information of China (English)

    Yuji Toiyama; Akira Mizoguchi; Kazushi Kimura; Junichirou Hiro; Yasuhiro Inoue; Tomonari Tutumi; Chikao Miki; Masato Kusunoki

    2007-01-01

    AIM: To investigate the expression patterns of TTYH2 in the human colon cancer and colon cancer cell lines and to evaluate the inhibitory effect of small interfering RNA (siRIMA) on the expression of TTYH2 in colon cancer cell lines.METHODS: We investigated the expression patterns of TTYH2 in colon cancer, adjacent non-tumorous colon mucosa, and cancer cell lines (DLD-1, caco-2, and Lovo) by RT-PCR. Furthermore, a siRNA plasmid expression vector against TTYH2 was constructed and transfected into DLD-1 and Caco-2 with LipofectamineTM 2000. The down regulation of TTYH2 expression was detected by RT-PCR and the role of siRNA in inducing cell proliferation and cell aggregation was evaluated by MTT and aggregation assay.RESULTS: TTYH2 gene expression in colon cancer tissue was significantly up-regulated compared with normal colonic mucosa (1.23 ± 0.404 vs 0.655 ± 0.373, P=0.0103). Colon cancer derived cell lines including DLD-1, Caco-2, and Lovo also expressed high levels of TTYH2. In contrast, transfection with siRNA-TTYH2 significantly inhibited both proliferation and scattering of these cancer cell lines.CONCLUSION: The present work demonstrates, for the first time, that the TTYH2 gene expression is significantly up-regulated in colon cancer. The TTYH2 gene may play an important role in regulating both proliferating and metastatic potentials of colorectal cancer.

  4. Combined Protein A and size exclusion high performance liquid chromatography for the single-step measurement of mAb, aggregates and host cell proteins.

    Science.gov (United States)

    Gjoka, Xhorxhi; Schofield, Mark; Cvetkovic, Aleksandar; Gantier, Rene

    2014-12-01

    Quantification of monoclonal antibody (mAb) monomer, mAb aggregates, and host cell proteins (HCPs) is critical for the optimization of the mAb production process. The present work describes a single high throughput analytical tool capable of tracking the concentration of mAb, mAb aggregate and HCPs in a growing cell culture batch. By combining two analytical HPLC methods, Protein A affinity and size-exclusion chromatography (SEC), it is possible to detect a relative increase or decrease in the concentration of all three entities simultaneously. A comparison of the combined Protein A-SEC assay to SEC alone was performed, demonstrating that it can be useful tool for the quantification of mAb monomer along with trending data for mAb aggregate and HCP. Furthermore, the study shows that the Protein A-SEC method is at least as accurate as other commonly used analytical methods such as ELISA and Bradford.

  5. Reducing and exaggerating escalation of commitment by option partitioning.

    Science.gov (United States)

    Kwong, Jessica Y Y; Wong, Kin Fai Ellick

    2014-07-01

    Options under escalation situations can be presented as a general class (e.g., investing in electronic products) or be partitioned into disjunctive suboptions within that class (e.g., investing in MP3 players, portable TV game consoles, and other electronic products). Drawing from the theoretical bases of partition priming and mental accounting, this research found support from 4 experiments that (a) a decision maker's commitment to a failing course of action is exaggerated when the escalation options are partitioned into multiple suboptions, whereas such commitment is reduced when the alternative options are portioned into suboptions, and (b) these partitioning effects are mediated by the subjective utility, including subjective values and probability, of the escalation option.

  6. Indole and synthetic derivative activate chaperone expression to reduce polyQ aggregation in SCA17 neuronal cell and slice culture models

    Directory of Open Access Journals (Sweden)

    Kung PJ

    2014-10-01

    Full Text Available Pin-Jui Kung,1,* Yu-Chen Tao,1,* Ho-Chiang Hsu,1 Wan-Ling Chen,1 Te-Hsien Lin,1 Donala Janreddy,2 Ching-Fa Yao,2 Kuo-Hsuan Chang,3 Jung-Yaw Lin,1 Ming-Tsan Su,1 Chung-Hsin Wu,1 Guey-Jen Lee-Chen,1 Hsiu-Mei Hsieh-Li1 1Department of Life Science, 2Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan; 3Department of Neurology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taipei, Taiwan *These authors contributed equally to this work Abstract: In spinocerebellar ataxia type 17 (SCA17, the expansion of a translated CAG repeat in the TATA box binding protein (TBP gene results in a long polyglutamine (polyQ tract in the TBP protein, leading to intracellular accumulation of aggregated TBP and cell death. The molecular chaperones act in preventing protein aggregation to ameliorate downstream harmful events. In this study, we used Tet-On SH-SY5Y cells with inducible SCA17 TBP/Q79-green fluorescent protein (GFP expression to test indole and synthetic derivative NC001-8 for neuroprotection. We found that indole and NC001-8 up-regulated chaperone expression to reduce polyQ aggregation in neuronal differentiated TBP/Q79 cells. The effects on promoting neurite outgrowth and on reduction of aggregation on Purkinje cells were also confirmed with cerebellar primary and slice cultures of SCA17 transgenic mice. Our results demonstrate how indole and derivative NC001-8 reduce polyQ aggregation to support their therapeutic potentials in SCA17 treatment. Keywords: spinocerebellar ataxia type 17, TATA box binding protein, polyQ aggregation, indole and derivative, therapeutics

  7. Resveratrol, Acetyl-Resveratrol, and Polydatin Exhibit Antigrowth Activity against 3D Cell Aggregates of the SKOV-3 and OVCAR-8 Ovarian Cancer Cell Lines

    Directory of Open Access Journals (Sweden)

    Simon J. Hogg

    2015-01-01

    Full Text Available Resveratrol has aroused significant scientific interest as it has been claimed that it exhibits a spectrum of health benefits. These include effects as an anti-inflammatory and an antitumour compound. The purpose of this study was to investigate and compare any potential antigrowth effects of resveratrol and two of its derivatives, acetyl-resveratrol and polydatin, on 3D cell aggregates of the EGFR/Her-2 positive and negative ovarian cancer cell lines SKOV-3 and OVCAR-8, respectively. Results showed that resveratrol and acetyl-resveratrol reduced cell growth in the SKOV-3 and OVCAR-8 in a dose-dependant manner. The growth reduction was mediated by the induction of apoptosis via the cleavage of poly(ADP-ribose polymerase (PARP-1. At lower concentrations, 5 and 10 µM, resveratrol, acetyl-resveratrol, and polydatin were less effective than higher concentrations, 50 and 100 µM. In SKOV-3 line, at higher concentrations, resveratrol and polydatin significantly reduced the phosphorylation of Her-2 and EGFR and the expression of Erk. Acetyl-resveratrol, on the other hand, did not change the activation of Her-2 and EGFR. Resveratrol, acetyl-resveratrol, and polydatin suppressed the secretion of VEGF in a dose-dependant fashion. In the OVCAR-8 cell line, resveratrol and acetyl-resveratrol at 5 and 10 µM increased the activation of Erk. Above these concentrations they decreased activation. Polydatin did not produce this effect. This study demonstrates that resveratrol and its derivatives may inhibit growth of 3D cell aggregates of ovarian cancer cell lines via different signalling molecules. Resveratrol and its derivatives, therefore, warrant further in vivo evaluation to assess their potential clinical utility.

  8. Small steps to maturity. Fuel cell heating aggregates; Muehsames Herantasten. Brennstoffzellen-Heizgeraete

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Wolfgang

    2009-07-15

    By 2015 at the latest, fuel cell heating systems are expected to be available to the end user after practical tests have been completed. The ultimate breakthrough is to be achieved by a funding project of several thousand million Euros of the German Federal Minister of Transportation, Construction and Urban Development (BMVBS). But the 2009 Hanover Fair showed that the development of fuel cell heating systems for serial production is a process of small steps taken one by one. Also, it becomes clear that the optimistic forecasts of a mass market that were sometimes voiced will not become reality. (orig.)

  9. Enhanced aggregation of androgen receptor in induced pluripotent stem cell-derived neurons from spinal and bulbar muscular atrophy.

    Science.gov (United States)

    Nihei, Yoshihiro; Ito, Daisuke; Okada, Yohei; Akamatsu, Wado; Yagi, Takuya; Yoshizaki, Takahito; Okano, Hideyuki; Suzuki, Norihiro

    2013-03-22

    Spinal and bulbar muscular atrophy (SBMA) is an X-linked motor neuron disease caused by a CAG repeat expansion in the androgen receptor (AR) gene. Ligand-dependent nuclear accumulation of mutant AR protein is a critical characteristic of the pathogenesis of SBMA. SBMA has been modeled in AR-overexpressing animals, but precisely how the polyglutamine (polyQ) expansion leads to neurodegeneration is unclear. Induced pluripotent stem cells (iPSCs) are a new technology that can be used to model human diseases, study pathogenic mechanisms, and develop novel drugs. We established SBMA patient-derived iPSCs, investigated their cellular biochemical characteristics, and found that SBMA-iPSCs can differentiate into motor neurons. The CAG repeat numbers in the AR gene of SBMA-iPSCs and also in the atrophin-1 gene of iPSCs derived from another polyQ disease, dentato-rubro-pallido-luysian atrophy (DRPLA), remain unchanged during reprogramming, long term passage, and differentiation, indicating that polyQ disease-associated CAG repeats are stable during maintenance of iPSCs. The level of AR expression is up-regulated by neuronal differentiation and treatment with the AR ligand dihydrotestosterone. Filter retardation assays indicated that aggregation of ARs following dihydrotestosterone treatment in neurons derived from SBMA-iPSCs increases significantly compared with neurological control iPSCs, easily recapitulating the pathological feature of mutant ARs in SBMA-iPSCs. This phenomenon was not observed in iPSCs and fibroblasts, thereby showing the neuron-dominant phenotype of this disease. Furthermore, the HSP90 inhibitor 17-allylaminogeldanamycin sharply decreased the level of aggregated AR in neurons derived from SBMA-iPSCs, indicating a potential for discovery and validation of candidate drugs. We found that SBMA-iPSCs possess disease-specific biochemical features and could thus open new avenues of research into not only SBMA, but also other polyglutamine diseases.

  10. Erythrocyte aggregation: Basic aspects and clinical importance

    OpenAIRE

    Oğuz K. Başkurt; Meiselman, Herbert J.

    2013-01-01

    Red blood cells (RBC) aggregate to form two- and three-dimensional structures when suspended in aqueous solutions containing large plasma proteins or polymers; this aggregation is reversible and shear dependent (i.e., dispersed at high shear and reformed at low or stasis). The extent of aggregation is the main determinant of low shear blood viscosity, thus predicting an inverse relationship between aggregation and in vivo blood flow. However, the effects of aggregation on hemodynamic mechanis...

  11. Submicron-Scale Heterogeneities in Nickel Sorption of Various Cell-Mineral Aggregates Formed by Fe(II)-Oxidizing Bacteria.

    Science.gov (United States)

    Schmid, Gregor; Zeitvogel, Fabian; Hao, Likai; Ingino, Pablo; Adaktylou, Irini; Eickhoff, Merle; Obst, Martin

    2016-01-01

    Fe(II)-oxidizing bacteria form biogenic cell-mineral aggregates (CMAs) composed of microbial cells, extracellular organic compounds, and ferric iron minerals. CMAs are capable of immobilizing large quantities of heavy metals, such as nickel, via sorption processes. CMAs play an important role for the fate of heavy metals in the environment, particularly in systems characterized by elevated concentrations of dissolved metals, such as mine drainage or contaminated sediments. We applied scanning transmission (soft) X-ray microscopy (STXM) spectrotomography for detailed 3D chemical mapping of nickel sorbed to CMAs on the submicron scale. We analyzed different CMAs produced by phototrophic or nitrate-reducing microbial Fe(II) oxidation and, in addition, a twisted stalk structure obtained from an environmental biofilm. Nickel showed a heterogeneous distribution and was found to be preferentially sorbed to biogenically precipitated iron minerals such as Fe(III)-(oxyhydr)oxides and, to a minor extent, associated with organic compounds. Some distinct nickel accumulations were identified on the surfaces of CMAs. Additional information obtained from scatter plots and angular distance maps, showing variations in the nickel-iron and nickel-organic carbon ratios, also revealed a general correlation between nickel and iron. Although a high correlation between nickel and iron was observed in 2D maps, 3D maps revealed this to be partly due to projection artifacts. In summary, by combining different approaches for data analysis, we unambiguously showed the heterogeneous sorption behavior of nickel to CMAs.

  12. Investigating the feasibility of scale up and automation of human induced pluripotent stem cells cultured in aggregates in feeder free conditions.

    Science.gov (United States)

    Soares, Filipa A C; Chandra, Amit; Thomas, Robert J; Pedersen, Roger A; Vallier, Ludovic; Williams, David J

    2014-03-10

    The transfer of a laboratory process into a manufacturing facility is one of the most critical steps required for the large scale production of cell-based therapy products. This study describes the first published protocol for scalable automated expansion of human induced pluripotent stem cell lines growing in aggregates in feeder-free and chemically defined medium. Cells were successfully transferred between different sites representative of research and manufacturing settings; and passaged manually and using the CompacT SelecT automation platform. Modified protocols were developed for the automated system and the management of cells aggregates (clumps) was identified as the critical step. Cellular morphology, pluripotency gene expression and differentiation into the three germ layers have been used compare the outcomes of manual and automated processes.

  13. Cell Communication during Aggregation and Development of the Cellular Slime Mould Distyostelium discoideum.

    Science.gov (United States)

    1985-01-01

    assistance, and love. With special feelings, I thank my beautiful daughters, Jennifer and Renata, for their many hugs and words of encouragement during times...cellularly throughout development (Bonner et al., 1969; Malkinson and Ashworth , 1972) and it has been suggested that cAMP may induce cells to enter...Axenic Liquid Media (Watts and Ashworth , 1970) Oxoid Bacteriological Peptone 14.3g Oxoid Yeast Extract 7.15g D-Glucose 15.4g Na .12H 20 1.28g KHt2P:O4

  14. Ectopic expression of cyclase associated protein CAP restores the streaming and aggregation defects of adenylyl cyclase a deficient Dictyostelium discoideum cells

    OpenAIRE

    Sultana Hameeda; Neelakanta Girish; Rivero Francisco; Blau-Wasser Rosemarie; Schleicher Michael; Noegel Angelika A

    2012-01-01

    Abstract Background Cell adhesion, an integral part of D. discoideum development, is important for morphogenesis and regulated gene expression in the multicellular context and is required to trigger cell-differentiation. G-protein linked adenylyl cyclase pathways are crucially involved and a mutant lacking the aggregation specific adenylyl cyclase ACA does not undergo multicellular development. Results Here, we have investigated the role of cyclase-associated protein (CAP), an important regul...

  15. A multifunctional probe with aggregation-induced emission characteristics for selective fluorescence imaging and photodynamic killing of bacteria over mammalian cells.

    Science.gov (United States)

    Gao, Meng; Hu, Qinglian; Feng, Guangxue; Tomczak, Nikodem; Liu, Rongrong; Xing, Bengang; Tang, Ben Zhong; Liu, Bin

    2015-04-02

    A multifunctional probe aggregation-induced emission-Zinc(II)-dipicolylamine (AIE-ZnDPA) is developed for selective targeting, fluorescence imaging, and photodynamic killing of both Gram-positive and Gram-negative bacteria over mammalian cells. The probe has significant advantages in simple probe design, enhanced fluorescence upon bacteria binding, excellent photostability, and broad-spectrum antibacterial activity with almost no harm to mammalian cells.

  16. Embryonic stem cells remain highly pluripotent following long term expansion as aggregates in suspension bioreactors.

    Science.gov (United States)

    zur Nieden, Nicole I; Cormier, Jaymi T; Rancourt, Derrick E; Kallos, Michael S

    2007-05-01

    Increasing attention has been drawn towards pluripotent embryonic stem cells (ESCs) and their potential use as the primary material in various tissue engineering applications. Successful clinical implementation of this technology would require a quality controlled reproducible culture system for the expansion of the cells to be used in the generation of functional tissues. Recently, we showed that suspension bioreactors could be used in the regulated large-scale expansion of highly pluripotent murine ESCs. The current study illustrates that these bioreactor protocols can be adapted for long term culture and that murine ESC cultures remain highly undifferentiated, when serially passaged in suspension bioreactors for extended periods. Flow cytometry analysis and gene expression profiles of several pluripotency markers, in addition to colony and embryoid body (EB) formation tests were conducted at the start and end of the experiment and all showed that the ESC cultures remained highly undifferentiated over extended culture time in suspension. In vivo teratoma formation and in vitro differentiation into neural, cardiomyocyte, osteoblast and chondrocyte lineages, performed at the end of the long term culture, further supported the presence of functional and undifferentiated ESCs in the expanded population. Overall, this system enables the controlled expansion of highly pluripotent murine ESC populations.

  17. Elevator and Escalator Safety Education for Older Adults.

    Science.gov (United States)

    Hanks, Roma Stovall

    1996-01-01

    In eight focus groups in five cities, older adults identified their concerns about safety on elevators and escalators, often related to misunderstanding of the equipment. Their preferences for delivery of safety information included video/television, pamphlets, discussions, and posters. Educational interventions and modifications for disabilities…

  18. Les escales de Likert poden augmentar en sensibilitat?

    Directory of Open Access Journals (Sweden)

    Rafel Bisquerra Alzina

    2015-07-01

    Full Text Available En les investigacions que utilitzen escales tipus Likert s’apliquen principalment escales de 5 punts, sense una fonamentació metodològica que ho justifiqui. La revisió de 3 conegudes revistes permet arribar a aquesta conclusió. Sembla que es fa així per tradició i perquè és difícil posar nom a més de cinc opcions de resposta. En aquest article es posa en qüestió aquesta tradició i s’aporten arguments per proposar altres alternatives. S’analitza la importància de millorar la sensibilitat de les escales augmentant les opcions de resposta; es recomana evitar l’ús de denominacions categòriques, que strictu sensu impedeix el seu ús com a escala d’interval ja que la converteix en nominal (categòrica; s’analitza el rebuig a valors extrems, etc. Com a conseqüència, es recomana la proposta en favor d’escales d’onze punts (de 0 a 10.

  19. Aggregate resources in the Netherlands

    NARCIS (Netherlands)

    Meulen, M.J. van der; Gessel, S.F. van; Veldkamp, J.G.

    2005-01-01

    We have built a 3D lithological model of the Netherlands, for the purpose of mapping on-land aggregate resources down to 50 m below the surface. The model consists of voxel cells (1000 · 1000 · 1 m), with lithological composition and aggregate content estimates as primary attributes. These attribute

  20. Construction aggregates

    Science.gov (United States)

    Nelson, T.I.; Bolen, W.P.

    2007-01-01

    Construction aggregates, primarily stone, sand and gravel, are recovered from widespread naturally occurring mineral deposits and processed for use primarily in the construction industry. They are mined, crushed, sorted by size and sold loose or combined with portland cement or asphaltic cement to make concrete products to build roads, houses, buildings, and other structures. Much smaller quantities are used in agriculture, cement manufacture, chemical and metallurgical processes, glass production and many other products.

  1. Dlgh1 coordinates actin polymerization, synaptic T cell receptor and lipid raft aggregation, and effector function in T cells.

    Science.gov (United States)

    Round, June L; Tomassian, Tamar; Zhang, Min; Patel, Viresh; Schoenberger, Stephen P; Miceli, M Carrie

    2005-02-07

    Lipid raft membrane compartmentalization and membrane-associated guanylate kinase (MAGUK) family molecular scaffolds function in establishing cell polarity and organizing signal transducers within epithelial cell junctions and neuronal synapses. Here, we elucidate a role for the MAGUK protein, Dlgh1, in polarized T cell synapse assembly and T cell function. We find that Dlgh1 translocates to the immune synapse and lipid rafts in response to T cell receptor (TCR)/CD28 engagement and that LckSH3-mediated interactions with Dlgh1 control its membrane targeting. TCR/CD28 engagement induces the formation of endogenous Lck-Dlgh1-Zap70-Wiskott-Aldrich syndrome protein (WASp) complexes in which Dlgh1 acts to facilitate interactions of Lck with Zap70 and WASp. Using small interfering RNA and overexpression approaches, we show that Dlgh1 promotes antigen-induced actin polymerization, synaptic raft and TCR clustering, nuclear factor of activated T cell activity, and cytokine production. We propose that Dlgh1 coordinates TCR/CD28-induced actin-driven T cell synapse assembly, signal transduction, and effector function. These findings highlight common molecular strategies used to regulate cell polarity, synapse assembly, and transducer organization in diverse cellular systems.

  2. Combined immunotherapy with granulocyte-macrophage colony-stimulating factor-transduced allogeneic prostate cancer cells and ipilimumab in patients with metastatic castration-resistant prostate cancer: a phase 1 dose-escalation trial

    NARCIS (Netherlands)

    Eertwegh, A.J. van den; Versluis, J.; Berg, H.P. van den; Santegoets, S.J.; Moorselaar, R.J. van; Sluis, T.M. van der; Gall, H.E.; Harding, T.C.; Jooss, K.; Lowy, I.; Pinedo, H.M.; Scheper, R.J.; Stam, A.G.; Blomberg, B.M. von; Gruijl, T.D. de; Hege, K.; Sacks, N.; Gerritsen, W.R.

    2012-01-01

    BACKGROUND: The granulocyte-macrophage colony-stimulating factor-transduced allogeneic prostate cancer cells vaccine (GVAX) has antitumour activity against prostate cancer; preclinical studies have shown potent synergy when combined with ipilimumab, an antibody that blocks cytotoxic T-lymphocyte ant

  3. Interplay Between Side Chain Pattern, Polymer Aggregation, and Charge Carrier Dynamics in PBDTTPD:PCBM Bulk-Heterojunction Solar Cells

    KAUST Repository

    Dyer-Smith, Clare

    2015-05-01

    Poly(benzo[1,2-b:4,5-b′]dithiophene–alt–thieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD) polymer donors with linear side-chains yield bulk-heterojunction (BHJ) solar cell power conversion efficiencies (PCEs) of about 4% with phenyl-C71-butyric acid methyl ester (PC71BM) as the acceptor, while a PBDTTPD polymer with a combination of branched and linear substituents yields a doubling of the PCE to 8%. Using transient optical spectroscopy it is shown that while the exciton dissociation and ultrafast charge generation steps are not strongly affected by the side chain modifications, the polymer with branched side chains exhibits a decreased rate of nongeminate recombination and a lower fraction of sub-nanosecond geminate recombination. In turn the yield of long-lived charge carriers increases, resulting in a 33% increase in short circuit current (J sc). In parallel, the two polymers show distinct grazing incidence X-ray scattering spectra indicative of the presence of stacks with different orientation patterns in optimized thin-film BHJ devices. Independent of the packing pattern the spectroscopic data also reveals the existence of polymer aggregates in the pristine polymer films as well as in both blends which trap excitons and hinder their dissociation.

  4. Abiotic factors in colony formation: effects of nutrition and light on extracellular polysaccharide production and cell aggregates of Microcystis aeruginosa

    Institute of Scientific and Technical Information of China (English)

    YANG Zhen; KONG Fanxiang

    2013-01-01

    Colony morphology is important for Microcystis to sustain a competitive advantage in eutrophic lakes.The mechanism of colony formation in Microcystis is currently unclear.Extracellular polysaccharide (EPS) has been reported to play an important role in cell aggregate formation of some phytoplankton.Microcystis aeruginosa was cultivated under varied abiotic conditions,including different nutrient,light,and temperature conditions,to investigate their effects on EPS production and morphological change.The results show that nutrient concentration and light intensity have great effects on EPS production in M.aeruginosa.There was a considerable increase in EPS production after M.aeruginosa was cultivated in adjusted culture conditions similar to those present in the field (28.9 mg C/L,1.98 mg N/L,0.65 mg P/L,light intensity:100 μmol/(m2·s)).These results indicate that abiotic factors might be one of the triggers for colony formation in Microcystis.

  5. Biased information processing in the escalation paradigm: information search and information evaluation as potential mediators of escalating commitment.

    Science.gov (United States)

    Schultze, Thomas; Pfeiffer, Felix; Schulz-Hardt, Stefan

    2012-01-01

    Escalation of commitment denotes decision makers' increased reinvestment of resources in a losing course of action. Despite the relevance of this topic, little is known about how information is processed in escalation situations, that is, whether decision makers who receive negative outcome feedback on their initial decision search for and/or process information biasedly and whether these biases contribute to escalating commitment. Contrary to a widely cited study by E. J. Conlon and J. M. Parks (1987), in 3 experiments, the authors found that biases do not occur on the level of information search. Neither in a direct replication and extension of the original study with largely increased test power (Experiment 1) nor under methodologically improved conditions (Experiments 2 and 3) did decision makers responsible for failure differ from nonresponsible decision makers with regards to information search, and no selective search for information supporting the initial decision or voting for further reinvestment was observed. However, Experiments 3 and 4 show that the evaluation of the previously sought information is biased among participants who were responsible for initiating the course of action. Mediation analyses show that this evaluation bias in favor of reinvestment partially mediated the responsibility effect on escalation of commitment.

  6. E4 - Energy efficient elevators and escalators. Barriers to and strategies for promoting energy-efficient lift and escalator technologies

    Energy Technology Data Exchange (ETDEWEB)

    Duetschke, Elisabeth; Hirzel, Simon

    2010-02-25

    According to prior findings of the E4 project, considerable savings potential exists both for lifts and escalators that could be realized if appropriate technology is implemented. However, energy-efficient technology is slowly diffusing the market - a phenomenon that could be explained by barriers present in the market. A barrier is defined as a mechanism that inhibits a decision or behavior that appears to be both energy-efficient and economically efficient and thereby prevents investment in energy-efficient technologies. This document has two aims. First, it will identify influential barriers in the European lift and escalator market. This analysis is based on the literature as well as a study including interviews as well as group discussions with relevant stakeholders. Second, strategies and measures to overcome the barriers identified in the first step are outlined. Major barriers to the penetration of energy-efficient technologies identified in this paper include a lack of monitoring energy consumption of installations and a lack of awareness of as well as knowledge about energy-efficient technology. Thus, installations and components are usually chosen without a (comprehensive) assessment of their energy consumption and without considering life-cycle approaches. On top of this, split incentives are a regularly occurring barrier. Various stakeholders are influential in the decisionmaking process about an installation or its components. However, those who will later pay for the energy consumption often are not involved in this process. Moreover, it is important to keep in mind that the number of new lifts and escalators installed each year is relatively low compared to the existing stock. Thus, it is very important to discuss enhancement of energy efficiency also for the existing stock. Based on our analyses, several recommendations are developed in this paper that could contribute to a market transformation in the lift and escalator market. First of all, a

  7. [Lysophosphatidic acid and human erythrocyte aggregation].

    Science.gov (United States)

    Sheremet'ev, Iu A; Popovicheva, A N; Levin, G Ia

    2014-01-01

    The effects of lysophosphatidic acid on the morphology and aggregation of human erythrocytes has been studied. Morphology of erythrocytes and their aggregates were studied by light microscopy. It has been shown that lysophosphatidic acid changes the shape of red blood cells: diskocyte become echinocytes. Aggregation of red blood cells (rouleaux) was significantly reduced in autoplasma. At the same time there is a strong aggregation of echinocytes. This was accompanied by the formation of microvesicles. Adding normal plasma to echinocytes restores shape and aggregation of red blood cells consisting of "rouleaux". A possible mechanism of action of lysophosphatidic acid on erythrocytes is discussed.

  8. Decreased platelet aggregation by shear stress-stimulated endothelial cells in vitro: description of a method and first results in diabetes.

    Science.gov (United States)

    De Franceschi, Maria S; Palange, Anna L; Mancuso, Anna; Grande, Laura; Muccari, Domenico; Scavelli, Faustina B; Irace, Concetta; Gnasso, Agostino; Carallo, Claudio

    2015-01-01

    The interaction between platelets and endothelium in vivo is a complex phenomenon. Our aim was to develop an in vitro system that mimics the in vivo environment and investigate platelet function in a common pathological condition. Human umbilical vein endothelial cells were used and platelets from 28 type 2 diabetes patients were studied under shear stress conditions. Mean coefficient of variation of platelet aggregation was 10% in dynamic conditions in the presence of endothelium. Endothelial cells increased the concentration of inductor needed to achieve 50% platelet aggregation to adenosine diphosphate from 2.6 ± 1.3 in static conditions to 3.7 ± 1.3 µM in dynamic conditions. A similar pattern was observed when collagen was used for platelet activation. Incubation of endothelium with a nitric oxide inhibitor abolished this effect, indicating platelet inhibitory effect of endothelial cells is nitric oxide mediated. Platelet reactivity of healthy controls was less influenced by the presence of endothelial cells and displayed reduced basal platelet reactivity compared with platelets from diabetes patients. We show that platelet aggregation in diabetes as commonly reported in vitro may not fully reflect the in vivo pathophysiological process. Future studies are warranted to investigate other pathological conditions and analyse the effects of antiplatelet agents using this system.

  9. Sequence-dependent internalization of aggregating peptides.

    Science.gov (United States)

    Couceiro, José R; Gallardo, Rodrigo; De Smet, Frederik; De Baets, Greet; Baatsen, Pieter; Annaert, Wim; Roose, Kenny; Saelens, Xavier; Schymkowitz, Joost; Rousseau, Frederic

    2015-01-02

    Recently, a number of aggregation disease polypeptides have been shown to spread from cell to cell, thereby displaying prionoid behavior. Studying aggregate internalization, however, is often hampered by the complex kinetics of the aggregation process, resulting in the concomitant uptake of aggregates of different sizes by competing mechanisms, which makes it difficult to isolate pathway-specific responses to aggregates. We designed synthetic aggregating peptides bearing different aggregation propensities with the aim of producing modes of uptake that are sufficiently distinct to differentially analyze the cellular response to internalization. We found that small acidic aggregates (≤500 nm in diameter) were taken up by nonspecific endocytosis as part of the fluid phase and traveled through the endosomal compartment to lysosomes. By contrast, bigger basic aggregates (>1 μm) were taken up through a mechanism dependent on cytoskeletal reorganization and membrane remodeling with the morphological hallmarks of phagocytosis. Importantly, the properties of these aggregates determined not only the mechanism of internalization but also the involvement of the proteostatic machinery (the assembly of interconnected networks that control the biogenesis, folding, trafficking, and degradation of proteins) in the process; whereas the internalization of small acidic aggregates is HSF1-independent, the uptake of larger basic aggregates was HSF1-dependent, requiring Hsp70. Our results show that the biophysical properties of aggregates determine both their mechanism of internalization and proteostatic response. It remains to be seen whether these differences in cellular response contribute to the particular role of specific aggregated proteins in disease.

  10. Ectopic expression of cyclase associated protein CAP restores the streaming and aggregation defects of adenylyl cyclase a deficient Dictyostelium discoideum cells

    Directory of Open Access Journals (Sweden)

    Sultana Hameeda

    2012-01-01

    Full Text Available Abstract Background Cell adhesion, an integral part of D. discoideum development, is important for morphogenesis and regulated gene expression in the multicellular context and is required to trigger cell-differentiation. G-protein linked adenylyl cyclase pathways are crucially involved and a mutant lacking the aggregation specific adenylyl cyclase ACA does not undergo multicellular development. Results Here, we have investigated the role of cyclase-associated protein (CAP, an important regulator of cell polarity and F-actin/G-actin ratio in the aca- mutant. We show that ectopic expression of GFP-CAP improves cell polarization, streaming and aggregation in aca- cells, but it fails to completely restore development. Our studies indicate a requirement of CAP in the ACA dependent signal transduction for progression of the development of unicellular amoebae into multicellular structures. The reduced expression of the cell adhesion molecule DdCAD1 together with csA is responsible for the defects in aca- cells to initiate multicellular development. Early development was restored by the expression of GFP-CAP that enhanced the DdCAD1 transcript levels and to a lesser extent the csA mRNA levels. Conclusions Collectively, our data shows a novel role of CAP in regulating cell adhesion mechanisms during development that might be envisioned to unravel the functions of mammalian CAP during animal embryogenesis.

  11. STUDY OF PRIVILEGE ESCALATION ATTACK ON ANDROID AND ITS COUNTERMEASURES

    Directory of Open Access Journals (Sweden)

    REJO MATHEW

    2012-09-01

    Full Text Available Android is most commonly used platform for smartphones today which boasts of an advanced security model having MAC and sandboxing. These features allow developers and users to restrict the execution of anapplication to the privileges assigned. The exploitation of vulnerabilities of the program is confined within the privilege boundaries of an applications sandbox. Privilege escalation attacks have grown manifold as the use of android systems have increased. Different kinds of mechanisms have provided some sort of respite to the developers but the security feature handling by the developers has not helped much. In this paper we discuss the basics of the privilege escalation attack and the various techniques used to counter and prevent this problem.

  12. Managing Conflict: Examining Recent PLA Writings on Escalation Control

    Science.gov (United States)

    2016-02-01

    On one hand, we see recognition in authoritative PLA works that, in theory, conflict or even war may result from an accidental crisis if it is... assets , the intensity of interaction, and the 44 We do not use the term “escalation ladder” here...The PLA Encyclopedia adds that war situation control includes control of “tangible land, sea, air and space battlefields” and of “ intangible

  13. Deterrence Adrift Mapping Conflict and Escalation in South Asia

    Science.gov (United States)

    2016-06-21

    lines in the bilateral deterrence relationship and chip away at India’s escalation dominance theory . The hedging action that has created the most...the battle areas to support its front lines and balance against a riposte, blurring the distinction between limited and general war. This action ...consequences are examined in detail below. India is likely to mobilize its three strike corps during any limited - aims ground campaign for two reasons . The first

  14. After the First Shots: Managing Escalation in Northeast Asia

    Science.gov (United States)

    2015-01-01

    other words, withholding punishment —to induce comparable restraint from the adversary. Madelyn Creedon, the former Assistant Secretary of Defense...measures for reinforcing mutual restraint in the early phase of a confrontation, but these measures would quickly become infeasible if China did...Measured punishment and operations that deny adversary objectives could influence its perceptions about both the costs of escalation and continuing

  15. Post-assembly atomic layer deposition of ultrathin metal-oxide coatings enhances the performance of an organic dye-sensitized solar cell by suppressing dye aggregation.

    Science.gov (United States)

    Son, Ho-Jin; Kim, Chul Hoon; Kim, Dong Wook; Jeong, Nak Cheon; Prasittichai, Chaiya; Luo, Langli; Wu, Jinsong; Farha, Omar K; Wasielewski, Michael R; Hupp, Joseph T

    2015-03-11

    Dye aggregation and concomitant reduction of dye excited-state lifetimes and electron-injection yields constitute a significant mechanism for diminution of light-to-electrical energy conversion efficiencies in many dye-sensitized solar cells (DSCs). For TiO2-based DSCs prepared with an archetypal donor-acceptor organic dye, (E)-2-cyano-3-(5'-(5''-(p-(diphenylamino)phenyl)-thiophen-2''-yl)thiophen-2'-yl)acrylic acid (OrgD), we find, in part via ultrafast spectroscopy measurements, that postdye-adsorption atomic layer deposition (ALD) of ultrathin layers of either TiO2 or Al2O3 effectively reverses residual aggregation. Notably, the ALD treatment is significantly more effective than the widely used aggregation-inhibiting coadsorbent, chenodeoxycholic acid. Primarily because of reversal of OrgD aggregation, and resulting improved injection yields, ALD post-treatment engenders a 30+% increase in overall energy conversion efficiency. A secondary contributor to increased currents and efficiencies is an ALD-induced attenuation of the rate of interception of injected electrons, resulting in slightly more efficient charge collection.

  16. Phylogenetic escalation and decline of plant defense strategies.

    Science.gov (United States)

    Agrawal, Anurag A; Fishbein, Mark

    2008-07-22

    As the basal resource in most food webs, plants have evolved myriad strategies to battle consumption by herbivores. Over the past 50 years, plant defense theories have been formulated to explain the remarkable variation in abundance, distribution, and diversity of secondary chemistry and other defensive traits. For example, classic theories of enemy-driven evolutionary dynamics have hypothesized that defensive traits escalate through the diversification process. Despite the fact that macroevolutionary patterns are an explicit part of defense theories, phylogenetic analyses have not been previously attempted to disentangle specific predictions concerning (i) investment in resistance traits, (ii) recovery after damage, and (iii) plant growth rate. We constructed a molecular phylogeny of 38 species of milkweed and tested four major predictions of defense theory using maximum-likelihood methods. We did not find support for the growth-rate hypothesis. Our key finding was a pattern of phyletic decline in the three most potent resistance traits (cardenolides, latex, and trichomes) and an escalation of regrowth ability. Our neontological approach complements more common paleontological approaches to discover directional trends in the evolution of life and points to the importance of natural enemies in the macroevolution of species. The finding of macroevolutionary escalating regowth ability and declining resistance provides a window into the ongoing coevolutionary dynamics between plants and herbivores and suggests a revision of classic plant defense theory. Where plants are primarily consumed by specialist herbivores, regrowth (or tolerance) may be favored over resistance traits during the diversification process.

  17. The effects of mortality salience on escalation of commitment.

    Science.gov (United States)

    Yen, Chih-Long; Lin, Chun-Yu

    2012-01-01

    Based on propositions derived from terror management theory (TMT), the current study proposes that people who are reminded of their mortality exhibit a higher degree of self-justification behavior to maintain their self-esteem. For this reason, they could be expected to stick with their previous decisions and invest an increasing amount of resources in those decisions, despite the fact that negative feedback has clearly indicated that they might be on a course toward failure (i.e., "escalation of commitment"). Our experiment showed that people who were reminded of their mortality were more likely to escalate their level of commitment by maintaining their current course of action. Two imaginary scenarios were tested. One of the scenarios involved deciding whether to send additional troops into the battlefield when previous attempts had failed; the other involved deciding whether to continue developing an anti-radar fighter plane when the enemy had already developed a device to detect it. The results supported our hypothesis that mortality salience increases the tendency to escalate one's level of commitment.

  18. Flu, risks, and videotape: escalating fear and avoidance.

    Science.gov (United States)

    Rosoff, Heather; John, Richard S; Prager, Fynnwin

    2012-04-01

    While extensive risk perception research has focused on emotions, cognitions, and behavior at static points in time, less attention has been paid to how these variables might change over time. This study assesses how negative affect, threat beliefs, perceived risk, and intended avoidance behavior change over the course of an escalating biological disaster. A scenario simulation methodology was used that presents respondents with a video simulation of a 15-day series of local news reports to immerse respondents in the developing details of the disaster. Systemic manipulation of the virus's causal origin (terrorist attack, medical lab accident, unknown) and the respondent's proximity to the virus (local vs. opposite coast) allowed us to investigate the dynamics of public response. The unfolding scenario was presented in discrete episodes, allowing responses to be tracked over the episodes. The sample includes 600 respondents equally split by sex and by location, with half in the Washington, DC area, and half in the Los Angeles area. The results showed respondents' reactions to the flu epidemic increased as the disaster escalated. More importantly, there was considerable consistency across respondents' emotional, cognitive, and behavioral responses to the epidemic over the episodes. In addition, the reactions of respondents proximally closer to the epidemic increased more rapidly and with greater intensity than their distant counterparts. Finally, as the flu epidemic escalated, both terrorist and accidental flu releases were perceived as being less risky and were less likely to lead to avoidance behavior compared to the unknown flu release.

  19. Neuroprotection of inositol hexaphosphate and changes of mitochondrion mediated apoptotic pathway and α-synuclein aggregation in 6-OHDA induced parkinson's disease cell model.

    Science.gov (United States)

    Zhang, Zheng; Hou, Lin; Li, Xianghong; Ju, Chuanxia; Zhang, Jinyu; Li, Xin; Wang, Xiuli; Liu, Cun; Lv, Yuqiang; Wang, Yuehua

    2016-02-15

    Animal and cell experiments showed that inositol hexaphosphate (IP6) was protective on neurons in parkinson's disease (PD) model, but the underlying mechanism of this action was not extensively elucidated. To address this question, we established 6-hydroxydopamine (6-OHDA) induced human dopaminergic cell line SH-SY5Y as PD cell model and testified the neuroprotection of IP6. Through hoechst nuclear stain method and flow cytometric analysis, apoptosis induced by 6-OHDA was blocked by IP6 pretreatment. Significant protection against reactive oxygen species (ROS) and lipid peroxidation product malondialdehyde (MDA) was observed in 6-OHDA induced cells pretreated with IP6. To further investigate the mechanism of anti-apoptotic effect of IP6, expression of mediators in mitochondrion dependent apoptotic pathway was detected. Results indicated that loss of mitochondrial membrane potential, cytochrome c releasing, upregulation of Bcl-2-associated X protein (Bax), downregulation of B-cell CLL/lymphoma 2 (Bcl-2) and caspases activation were reversed by IP6. In addition, using flow cytometric method and western blot approach, our data showed that IP6 attenuated the rise of calcium and α-synuclein aggregation in cytosol. Collectively, IP6 exerted its neuroprotection on dopaminergic cells in PD cell model and the mechanism may be associated with changes of mitochondrion mediated apoptotic pathway and α-synuclein aggregation.

  20. Arginine-glycine-aspartic acid-polyethylene glycol-polyamidoamine dendrimer conjugate improves liver-cell aggregation and function in 3-D spheroid culture.

    Science.gov (United States)

    Chen, Zhanfei; Lian, Fen; Wang, Xiaoqian; Chen, Yanling; Tang, Nanhong

    The polyamidoamine (PAMAM) dendrimer, a type of macromolecule material, has been used in spheroidal cell culture and drug delivery in recent years. However, PAMAM is not involved in the study of hepatic cell-spheroid culture or its biological activity, particularly in detoxification function. Here, we constructed a PAMAM-dendrimer conjugate decorated by an integrin ligand: arginine-glycine-aspartic acid (RGD) peptide. Our studies demonstrate that RGD-polyethylene glycol (PEG)-PAMAM conjugates can promote singly floating hepatic cells to aggregate together in a sphere-like growth with a weak reactive oxygen species. Moreover, RGD-PEG-PAMAM conjugates can activate the AKT-MAPK pathway in hepatic cells to promote cell proliferation and improve basic function and ammonia metabolism. Together, our data support the hepatocyte sphere treated by RGD-PEG-PAMAM conjugates as a potential source of hepatic cells for a biological artificial liver system.

  1. A pyrene-benzthiazolium conjugate portraying aggregation induced emission, a ratiometric detection and live cell visualization of HSO{sub 3}{sup −}

    Energy Technology Data Exchange (ETDEWEB)

    Diwan, Uzra; Kumar, Virendra [Department of Chemistry (Centre of Advanced Study), Faculty of Science, Banaras Hindu University, Varanasi, Uttar Pradesh 221005 (India); Mishra, Rakesh K. [Photosciences and Photonics, Chemical Sciences and Technology Division, CSIR–National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019 (India); Rana, Nishant Kumar; Koch, Biplob; Singh, Manish Kumar [Department of Zoology (Centre of Advanced Study), Faculty of Science, Banaras Hindu University, Varanasi 221005 (India); Upadhyay, K.K., E-mail: drkaushalbhu@yahoo.co.in [Department of Chemistry (Centre of Advanced Study), Faculty of Science, Banaras Hindu University, Varanasi, Uttar Pradesh 221005 (India)

    2016-07-27

    The present study deals with the photophysical property of a pyrene-benzthiazolium conjugate R1, as a strong intramolecular charge transfer (ICT) probe exhibiting long wavelength emission in the red region. Unlike traditional planar polyaromatic hydrocarbons whose aggregation generally quenches the light emission, the pyrene based R1 was found to display aggregation-induced emission (AIE) property along with simultaneous increase in its quantum yield upon increasing the water content of the medium. The R1 exhibits high specificity towards HSO{sub 3}{sup −}/SO{sub 3}{sup 2−} by interrupting its own ICT producing there upon a large ratiometric blue shift of ∼220 nm in its emission spectrum. The lowest detection limit for the above measurement was found to be 8.90 × 10{sup −8} M. The fluorescent detection of HSO{sub 3}{sup −} was also demonstrated excellently by test paper strip and silica coated TLC plate incorporating R1. The live cell imaging of HSO{sub 3}{sup −} through R1 in HeLa cells was studied using fluorescence microscopic studies. The particle size and morphological features of R1 and R1-HSO{sub 3}{sup −} aggregates in aqueous solution were characterized by DLS along with SEM analysis.- Highlights: • A pyrene-benzthiazolium conjugate probe (R1) itself showed interesting phenomenon of an aggregation-induced emission (AIE). • R1 emits in the red channel and effectively utilized as a colorimetric and ratiometric fluorescent sensor for HSO{sub 3}{sup −}. • The nano-dimensional spherical particles of R1 got enlarged upon its interaction with the HSO{sub 3}{sup −}. • R1 can efficiently stain HSO{sub 3}{sup −} in live cells and can be used for the on-spot detection of the same.

  2. Effects of simvastatin/ezetimibe on microparticles, endothelial progenitor cells and platelet aggregation in subjects with coronary heart disease under antiplatelet therapy

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, L.M.; França, C.N.; Izar, M.C.; Bianco, H.T.; Lins, L.S.; Barbosa, S.P.; Pinheiro, L.F.; Fonseca, F.A.H. [Universidade Federal de São Paulo, Escola Paulista de Medicina, Departamento de Medicina, São Paulo, SP, Brasil, Departamento de Medicina, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP (Brazil)

    2014-04-15

    It is not known whether the addition of ezetimibe to statins adds cardiovascular protection beyond the expected changes in lipid levels. Subjects with coronary heart disease were treated with four consecutive 1-week courses of therapy (T) and evaluations. The courses were: T1, 100 mg aspirin alone; T2, 100 mg aspirin and 40 mg simvastatin/10 mg ezetimibe; T3, 40 mg simvastatin/10 mg ezetimibe, and 75 mg clopidogrel (300 mg initial loading dose); T4, 75 mg clopidogrel alone. Platelet aggregation was examined in whole blood. Endothelial microparticles (CD51), platelet microparticles (CD42/CD31), and endothelial progenitor cells (CD34/CD133; CDKDR/CD133, or CD34/KDR) were quantified by flow cytometry. Endothelial function was examined by flow-mediated dilation. Comparisons between therapies revealed differences in lipids (T2 and T3T1 and T4, P=0.001). Decreased platelet aggregation was observed after aspirin (arachidonic acid, T1aggregation, the amount of circulating endothelial and platelet microparticles, or endothelial progenitor cells. Cardiovascular protection following therapy with simvastatin/ezetimibe seems restricted to lipid changes and improvement of endothelial function not affecting the release of microparticles, mobilization of endothelial progenitor cells or decreased platelet aggregation.

  3. Reinjury risk of nano-calcium oxalate monohydrate and calcium oxalate dihydrate crystals on injured renal epithelial cells: aggravation of crystal adhesion and aggregation

    Science.gov (United States)

    Gan, Qiong-Zhi; Sun, Xin-Yuan; Bhadja, Poonam; Yao, Xiu-Qiong; Ouyang, Jian-Ming

    2016-01-01

    Background Renal epithelial cell injury facilitates crystal adhesion to cell surface and serves as a key step in renal stone formation. However, the effects of cell injury on the adhesion of nano-calcium oxalate crystals and the nano-crystal-induced reinjury risk of injured cells remain unclear. Methods African green monkey renal epithelial (Vero) cells were injured with H2O2 to establish a cell injury model. Cell viability, superoxide dismutase (SOD) activity, malonaldehyde (MDA) content, propidium iodide staining, hematoxylin–eosin staining, reactive oxygen species production, and mitochondrial membrane potential (Δψm) were determined to examine cell injury during adhesion. Changes in the surface structure of H2O2-injured cells were assessed through atomic force microscopy. The altered expression of hyaluronan during adhesion was examined through laser scanning confocal microscopy. The adhesion of nano-calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) crystals to Vero cells was observed through scanning electron microscopy. Nano-COM and COD binding was quantitatively determined through inductively coupled plasma emission spectrometry. Results The expression of hyaluronan on the cell surface was increased during wound healing because of Vero cell injury. The structure and function of the cell membrane were also altered by cell injury; thus, nano-crystal adhesion occurred. The ability of nano-COM to adhere to the injured Vero cells was higher than that of nano-COD crystals. The cell viability, SOD activity, and Δψm decreased when nano-crystals attached to the cell surface. By contrast, the MDA content, reactive oxygen species production, and cell death rate increased. Conclusion Cell injury contributes to crystal adhesion to Vero cell surface. The attached nano-COM and COD crystals can aggravate Vero cell injury. As a consequence, crystal adhesion and aggregation are enhanced. These findings provide further insights into kidney stone

  4. Sialylation of E-cadherin does not change the spontaneous or ET-18-OMe-mediated aggregation of MCF-7 human breast cancer cells.

    Science.gov (United States)

    Steelant, W F; Recchi, M A; Noë, V T; Boilly-Marer, Y; Bruyneel, E A; Verbert, A; Mareel, M M; Delannoy, P

    1999-05-01

    We have investigated the role of sialylation on cell-cell adhesion mediated by E-cadherin. Two MCF-7 human breast cancer cell variants were studied: MCF-7/AZ cells showed a spontaneous cell-cell adhesion in the fast and slow aggregation assay. whereas the adhesion deficient MCF-7/6 cell variant failed to form larger aggregates, suggesting that E-cadherin was not functional under the conditions of both assays. We measured the sialyltransferase activities using Galbeta1-3GalNAcalpha-O-benzyl and Galbeta1-4GlcNAcalpha-O-benzyl as acceptor substrates as well as mRNA levels of four sialyltransferases, ST3Gal I, ST3Gal III, ST3Gal IV, ST6Gal I, using multiplex RT-PCR in MCF-7 cell variants. The alpha2-6 and alpha2-3 sialylation of E-cadherin was investigated by immuno-blot using Sambucus nigra agglutinin and Maackia amurensis agglutinin. Compared to the adhesion-proficient MCF-7/AZ cells, the adhesion-deficient MCF-7/6 cell line apparently lacks ST6Gal I mRNA, has a lower ST3Gal I mRNA, a lower ST3Gal I sialyltransferase activity, and no alpha2-3 linked sialic acid moieties on E-cadherin. The potential anti-cancer drug 1-O-octadecyl-2-O-methylglycero-3-phosphocholine (ET-18-OMe, 48 h, 25 microg/ml) belonging to the class of alkyllysophospholipids restored the E-cadherin function in the adhesion-deficient MCF-7/6 cells as evidenced by an increased aggregation. ET-18-OMe caused loss of ST6Gal I mRNA in MCF-7/AZ cells but no changes of sialyltransferase activities or sialic acid moieties on E-cadherin could be observed. We conclude that Ca2+-dependent, E-cadherin-specific homotypic adhesion of MCF-7/AZ or MCF-7/6 cells treated with ET-18-OMe was not affected by sialylation of E-cadherin.

  5. Reduced IL-35 levels are associated with increased platelet aggregation and activation in patients with acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation.

    Science.gov (United States)

    Zhang, Xiaohui; Zhou, Yi; Xu, Lanping; Han, Wei; Chen, Huan; Chen, Yuhong; Fu, Haixia; Zhou, Shiyuan; Zhao, Jingzhong; Wang, Qianming; Feng, Feier; Zhu, Xiaolu; Liu, Kaiyan; Huang, Xiaojun

    2015-05-01

    Acute graft-versus-host disease (aGVHD) is a major complication associated with allogeneic hematopoietic stem cell transplantation (allo-HSCT). Interleukin (IL)-35 is a novel anti-inflammatory cytokine that suppresses the immune response. This prospective study explored IL-35 plasma levels in 65 patients after HSCT. The results revealed that the peripheral blood of patients with grades III-IV aGVHD (23.46 ng/ml) had reduced IL-35 compared to transplanted patients with grades I-II aGVHD (40.26 ng/ml, p IL-35 levels with respect to aGVHD. The patients who received lower levels of IL-35 cells in the GBM (28.0 ng/ml, p = 0.551) or lower levels of IL-35 in PBPC (53.46 ng/ml, p = 0.03) exhibited a higher incidence of aGVHD. Patients with aGVHD have increased platelet aggregation. IL-35 was added to patient blood in vitro, and platelet aggregation was inhibited by IL-35 in a dose-dependent manner. The markers of platelet activation (CD62P/PAC-1) can also be inhibited by IL-35. The results indicate that IL-35 may affect the development of aGVHD by inhibiting platelet activation and aggregation. Our data suggests that IL-35 represents a potentially effective therapeutic agent against aGVHD after allo-HSCT.

  6. Inhibition of β-amyloid Aggregation By Albiflorin, Aloeemodin And Neohesperidin And Their Neuroprotective Effect On Primary Hippocampal Cells Against β-amyloid Induced Toxicity.

    Science.gov (United States)

    Ho, See-Lok; Poon, Chung-Yan; Lin, Chengyuan; Yan, Ting; Kwong, Daniel Wai-Jing; Yung, Ken Kin-Lam; Wong, Man S; Bian, Zhaoxiang; Li, Hung-Wing

    2015-01-01

    Being one of the hallmarks of Alzheimer's disease, β-amyloid (Aβ) aggregates induce complicated neurotoxicity. Evidences show that the underlying mechanism of neurotoxicity involves a glutamate receptor subtype, N-methyl-D-aspartate (NMDA) receptor, an increase in intracellular calcium(II) ion loading as well as an elevation in oxidation stress. In this work, among the 35 chemical components of Chinese herbal medicines (CHMs) being screened for inhibitors of Aβ aggregation, four of them, namely albiflorin, aloeemodin, neohesperidin and physcion, were found for the first time to exhibit a potent inhibitory effect on Aβ(1-40) and Aβ(1-42) aggregation. Their neuroprotective capability on primary hippocampal neuronal cells was also investigated by MTT assay, ROS assay and intracellular calcium(II) ion concentration measurement. It was interesting to find that physcion was rather toxic to neuronal cells while albiflorin, aloeemodin and neohesperidin reduced the toxicity and ROS induced by both monomeric and oligomeric Aβ species. In addition, albiflorin was particularly powerful in maintaining the intracellular Ca(2+) concentration.

  7. Efficient generation of germ line transmitting chimeras from C57BL/6N ES cells by aggregation with outbred host embryos.

    Directory of Open Access Journals (Sweden)

    Marina Gertsenstein

    Full Text Available Genetically modified mouse strains derived from embryonic stem (ES cells have become essential tools for functional genomics and biomedical research. Large scale mutagenesis projects are producing libraries of mutant C57BL/6 (B6 ES cells to enable the functional annotation of every gene of the mouse genome. To realize the utility of these resources, efficient and accessible methods of generating mutant mice from these ES cells are necessary. Here, we describe a combination of ICR morula aggregation and a chemically-defined culture medium with widely available and accessible components for the high efficiency generation of germline transmitting chimeras from C57BL/6N ES cells. Together these methods will ease the access of the broader biomedical research community to the publicly available B6 ES cell resources.

  8. Role of multicellular aggregates in biofilm formation

    DEFF Research Database (Denmark)

    Kragh, Kasper N.; Hutchison, Jaime B.; Melaugh, Gavin

    2016-01-01

    In traditional models of in vitro biofilm development, individual bacterial cells seed a surface, multiply, and mature into multicellular, three-dimensional structures. Much research has been devoted to elucidating the mechanisms governing the initial attachment of single cells to surfaces. However......, in natural environments and during infection, bacterial cells tend to clump as multicellular aggregates, and biofilms can also slough off aggregates as a part of the dispersal process. This makes it likely that biofilms are often seeded by aggregates and single cells, yet how these aggregates impact biofilm...... initiation and development is not known. Here we use a combination of experimental and computational approaches to determine the relative fitness of single cells and preformed aggregates during early development of Pseudomonas aeruginosa biofilms. We find that the relative fitness of aggregates depends...

  9. Formation of Tethers from Spreading Cellular Aggregates.

    Science.gov (United States)

    Beaune, Grégory; Winnik, Françoise M; Brochard-Wyart, Françoise

    2015-12-01

    Membrane tubes are commonly extruded from cells and vesicles when a point-like force is applied on the membrane. We report here the unexpected formation of membrane tubes from lymph node cancer prostate (LNCaP) cell aggregates in the absence of external applied forces. The spreading of LNCaP aggregates deposited on adhesive glass substrates coated with fibronectin is very limited because cell-cell adhesion is stronger than cell-substrate adhesion. Some cells on the aggregate periphery are very motile and try to escape from the aggregate, leading to the formation of membrane tubes. Tethered networks and exchange of cargos between cells were observed as well. Growth of the tubes is followed by either tube retraction or tube rupture. Hence, even very cohesive cells are successful in escaping aggregates, which may lead to epithelial mesenchymal transition and tumor metastasis. We interpret the dynamics of formation and retraction of tubes in the framework of membrane mechanics.

  10. CONTROL SYSTEM FOR ESCALATOR = SISTEMA DE CONTROLE PARA ESCADA ROLANTE

    Directory of Open Access Journals (Sweden)

    Mauricio Ginez Romero

    2010-01-01

    Full Text Available Many business stablisment utilize escalator that performs it’s function in a regular way of work. There is a big waste of eletric power, as in a good part of it there isn’t a transportation of user. The search for new sources shouldnt’t is the only worry in the context of energetic resource, but also the development of new technologies aimed an optimal use of this recourse. In the conjuncture, this project aims to establish a escalators’ control system, to optimize their use and reduce energy consumption of equipment. The system’s operation is based on the principle that, after a time ta,, a free flow of user, which this time is previously define by a statistician study the escalator reduce its speed, if it has passed a time tb, being tb>ta, the escalator is stopped. If we have the presence of the user, the escalator presents low acceleration, establishing the regular way of work without risks of utilization. The energetic economy happens when the escalator is stopped, or working with reduced speed. The project consists in replace the eletric command of the reversor and with the direct start, by a system’s control proposed. The reduction of the energy comsumption was valued by a statistician study, so trough it we can increase the use of the system and stipulate of the economy zone for the escalators with high and low user’s flow. This system is ecologically correct and contribute for the consumption optimized of electric power. = Muitos estabelecimentos comerciais utilizam escadas rolantes que desempenham sua função em regime normal de funcionamento. Existe um grande desperdício de energia elétrica, já que em boa parte não há transporte de usuário. A busca por novas fontes não deve ser a única preocupação no contexto dos recursos energéticos, mas também o desenvolvimento de novas tecnologias que visam o uso otimizado destes recursos. Nesta conjuntura, este projeto visa implantar um sistema de controle para escadas

  11. Binding of heavy metal ions in aggregates of microbial cells, EPS and biogenic iron minerals measured in-situ using metal- and glycoconjugates-specific fluorophores

    Science.gov (United States)

    Hao, Likai; Guo, Yuan; Byrne, James M.; Zeitvogel, Fabian; Schmid, Gregor; Ingino, Pablo; Li, Jianli; Neu, Thomas R.; Swanner, Elizabeth D.; Kappler, Andreas; Obst, Martin

    2016-05-01

    Aggregates consisting of bacterial cells, extracellular polymeric substances (EPS) and Fe(III) minerals formed by Fe(II)-oxidizing bacteria are common at bulk or microscale chemical interfaces where Fe cycling occurs. The high sorption capacity and binding capacity of cells, EPS, and minerals controls the mobility and fate of heavy metals. However, it remains unclear to which of these component(s) the metals will bind in complex aggregates. To clarify this question, the present study focuses on 3D mapping of heavy metals sorbed to cells, glycoconjugates that comprise the majority of EPS constituents, and Fe(III) mineral aggregates formed by the phototrophic Fe(II)-oxidizing bacteria Rhodobacter ferrooxidans SW2 using confocal laser scanning microscopy (CLSM) in combination with metal- and glycoconjugates-specific fluorophores. The present study evaluated the influence of glycoconjugates, microbial cell surfaces, and (biogenic) Fe(III) minerals, and the availability of ferrous and ferric iron on heavy metal sorption. Analyses in this study provide detailed knowledge on the spatial distribution of metal ions in the aggregates at the sub-μm scale, which is essential to understand the underlying mechanisms of microbe-mineral-metal interactions. The heavy metals (Au3+, Cd2+, Cr3+, CrO42-, Cu2+, Hg2+, Ni2+, Pd2+, tributyltin (TBT) and Zn2+) were found mainly sorbed to cell surfaces, present within the glycoconjugates matrix, and bound to the mineral surfaces, but not incorporated into the biogenic Fe(III) minerals. Statistical analysis revealed that all ten heavy metals tested showed relatively similar sorption behavior that was affected by the presence of sorbed ferrous and ferric iron. Results in this study showed that in addition to the mineral surfaces, both bacterial cell surfaces and the glycoconjugates provided most of sorption sites for heavy metals. Simultaneously, ferrous and ferric iron ions competed with the heavy metals for sorption sites on the organic

  12. Isolation and measurement of the features of arrays of cell aggregates formed by dielectrophoresis using the user-specified Multi Regions Masking (MRM) technique

    Energy Technology Data Exchange (ETDEWEB)

    Yusvana, Rama; Markx, Gerard H [School of Engineering and Physical Science, Department of Chemical Engineering, Heriot-Watt University, Riccarton Campus, Edinburgh - EH14 4AS (United Kingdom); Headon, Denis, E-mail: g.h.markx@hw.ac.u [Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, Midlothian, Edinburgh - EH25 9PS (United Kingdom)

    2009-08-01

    The use of dielectrophoresis for the construction of artificial skin tissue with skin cells in follicle-like 3D cell aggregates in well-defined patterns is demonstrated. To analyse the patterns produced and to study their development after their formation a Virtual Instrument (VI) system was developed using the LabVIEW IMAQ Vision Development Module. A series of programming functions (algorithms) was used to isolate the features on the image (in our case; the patterned aggregates) and separate them from all other unwanted regions on the image. The image was subsequently converted into a binary version, covering only the desired microarray regions which could then be analysed by computer for automatic object measurements. The analysis utilized the simple and easy-to-use User-Specified Multi-Regions Masking (MRM) technique, which allows one to concentrate the analysis on the desired regions specified in the mask. This simplified the algorithms for the analysis of images of cell arrays having similar geometrical properties. By having a collection of scripts containing masks of different patterns, it was possible to quickly and efficiently develop sets of custom virtual instruments for the offline or online analysis of images of cell arrays in the database.

  13. Engineering new bone via a minimally invasive route using human bone marrow-derived stromal cell aggregates, microceramic particles, and human platelet-rich plasma gel.

    Science.gov (United States)

    Chatterjea, Anindita; Yuan, Huipin; Fennema, Eelco; Burer, Ruben; Chatterjea, Supriyo; Garritsen, Henk; Renard, Auke; van Blitterswijk, Clemens A; de Boer, Jan

    2013-02-01

    There is a rise in the popularity of arthroscopic procedures in orthopedics. However, the majority of cell-based bone tissue-engineered constructs (TECs) rely on solid preformed scaffolding materials, which require large incisions and extensive dissections for placement at the defect site. Thus, they are not suitable for minimally invasive techniques. The aim of this study was to develop a clinically relevant, easily moldable, bone TEC, amenable to minimally invasive techniques, using human mesenchymal stromal cells (hMSCs) and calcium phosphate microparticles in combination with an in situ forming platelet-rich plasma gel obtained from human platelets. Most conventional TECs rely on seeding and culturing single-cell suspensions of hMSCs on scaffolds. However, for generating TECs amenable to the minimally invasive approach, it was essential to aggregate the hMSCs in vitro before seeding them on the scaffolds as unaggregated MSCs did not generate any bone. Twenty four hours of in vitro aggregation was determined to be optimal for maintaining cell viability in vitro and bone formation in vivo. Moreover, no statistically significant difference was observed in the amount of bone formed when the TECs were implanted via an open approach or a minimally invasive route. TECs generated using MSCs from three different human donors generated new bone through the minimally invasive route in a reproducible manner, suggesting that these TECs could be a viable alternative to preformed scaffolds employed through an open surgery for treating bone defects.

  14. Cucurbitacin B induces rapid depletion of the G-actin pool through reactive oxygen species-dependent actin aggregation in melanoma cells

    Institute of Scientific and Technical Information of China (English)

    Yanting Zhang; Dongyun Ouyang; Lihui Xu; Yuhua Ji; Qingbing Zha; Jiye Cai; Xianhui He

    2011-01-01

    Cucurbitacin B (CuB), a triterpenoid compound isolated from Cucurbitaceae plants, has been reported as a promising anti-cancer agent, yet its action mechanism is still controversial. In this study, we explored the potential mechanism of CuB in murine B16F10 melanoma cells.Anti-proliferation and anti-invasion effects were assessed in cultured cells, and in vivo anti-tumor activity was evaluated in a murine subcutaneous melanoma model. Flow cytometry was adopted to analyze cell cycle distribution and reactive oxygen species (ROS) levels. Actin levels were determined by western blot analysis, and the profiles of differential expressed proteins were identified by a quantitative proteomic approach. The results showed that CuB exerted inhibitory effects on cell proliferation, colony formation, as well as migration and invasion potential of the melanoma cells. The growth of subcutaneous melanoma was significantly inhibited in mice treated with CuB when compared with control group. Furthermore,CuB treatment caused rapid cell membrane blebbing and deformation, and induced G2/M-phase arrest and formation of multiploid cells. Notably, the G-actin pool was rapidly depleted and actin aggregates were formed quickly after CuB treatment. A number of cytoskeleton-regulatory proteins were differentially regulated. Blockage of ROS production significantly reduced the G-actin depletion ability and the anti-tumor activity of CuB. These findings indicate that CuB induces rapid depletion of the G-actin pool through ROS-dependent actin aggregation in melanoma cells, which may at least partly account for its anti-tumor activity.

  15. Shift in aggregation, ROS generation, antioxidative defense, lysozyme and acetylcholinesterase activities in the cells of an Indian freshwater sponge exposed to washing soda (sodium carbonate).

    Science.gov (United States)

    Mukherjee, Soumalya; Ray, Mitali; Ray, Sajal

    2016-09-01

    Washing soda, chemically identified as anhydrous sodium carbonate, is a popular cleaning agent among the rural and urban populations of India which often contaminates the freshwater ponds and lakes, the natural habitat of sponge Eunapius carteri. Present investigation deals with estimation of cellular aggregation, generation of ROS and activities of antioxidant enzymes, lysozyme and acetylcholinesterase in the cells of E. carteri under the environmentally realistic concentrations of washing soda. Prolonged treatment of washing soda inhibited the degree of cellular aggregation. Experimental exposure of 8 and 16mg/l of sodium carbonate for 48h elevated the physiological level of reactive oxygen species (ROS) generation in the agranulocytes, semigranulocytes and granulocytes of E. carteri, whereas, treatment of 192h inhibited the ROS generation in three cellular morphotypes. Activities of superoxide dismutase, catalase and glutathione-S-transferase were recorded to be inhibited under prolonged exposure of washing soda. Washing soda mediated inhibition of ROS generation and depletion in the activities of antioxidant enzymes were indicative to an undesirable shift in cytotoxic status and antioxidative defense in E. carteri. Inhibition in the activity of lysozyme under the treatment of sodium carbonate was suggestive to a severe impairment of the innate immunological efficiency of E. carteri distributed in the washing soda contaminated habitat. Washing soda mediated inhibition in the activity of acetylcholinesterase indicated its neurotoxicity in E. carteri. Washing soda, a reported environmental contaminant, affected adversely the immunophysiological status of E. carteri with reference to cellular aggregation, oxidative stress, antioxidative defense, lysozyme and acetylcholinesterase activity.

  16. J-Aggregates of Amphiphilic Cyanine Dyes for Dye-Sensitized Solar Cells: A Combination between Computational Chemistry and Experimental Device Physics

    Directory of Open Access Journals (Sweden)

    M. S. A. Abdel-Mottaleb

    2014-01-01

    Full Text Available We report on the design and structure principles of 5,5′-6,6′-tetrachloro-1,1′-dioctyl-3,3′-bis-(3-carboxypropyl-benzimidacarbocyanine (Dye 1. Such metal-free amphiphilic cyanine dyes have many applications in dye-sensitized solar cells. AFM surface topographic investigation of amphiphilic molecules of Dye 1 adsorbed on TiO2 anode reveals the ability of spontaneous self-organization into highly ordered aggregates of fiber-like structure. These aggregates are known to exhibit outstanding optical properties of J-aggregates, namely, efficient exciton coupling and fast exciton energy migration, which are essential for building up artificial light harvesting to the photovoltaic device. A light-to-electricity conversion efficiency of DSSC based on the metal free amphiphilic Dye 1 is η=3.75, which is about 50% of that based on metal-based N719 Ru-dye (Di-tetrabutylammoniumcis-bis(isothiocyanatobis(2,2′-bipyridyl-4,4′-dicarboxylatoruthenium(II. DFT and TD-DFT studies show that large intramolecular charge transfer takes place from the HOMO to LUMO. HOMO is localized on a part of the molecule with almost no contribution from the carboxylic moiety. This clearly indicates that the anchoring carboxylic group plays a minor role.

  17. Final technical report for project titled Quantitative Characterization of Cell Aggregation/Adhesion as Predictor for Distribution and Transport of Microorganisms in Subsurface Environment

    Energy Technology Data Exchange (ETDEWEB)

    Gu, April Z. [Northeastern Univ., Boston, MA (United States); Wan, Kai-tak [Northeastern Univ., Boston, MA (United States)

    2014-09-02

    This project aims to explore and develop enabling methodology and techniques for nano-scale characterization of microbe cell surface contact mechanics, interactions and adhesion quantities that allow for identification and quantification of indicative properties related to microorganism migration and transport behavior in porous media and in subsurface environments. Microbe transport has wide impact and therefore is of great interest in various environmental applications such as in situ or enhanced subsurface bioremediation,filtration processes for water and wastewater treatments and protection of drinking water supplies. Although great progress has been made towards understanding the identities and activities of these microorganisms in the subsurface, to date, little is known of the mechanisms that govern the mobility and transport of microorganisms in DOE’s contaminated sites, making the outcomes of in situ natural attenuation or contaminant stability enhancement unpredictable. Conventionally, movement of microorganisms was believed to follows the rules governing solute (particle) transport. However, recent studies revealed that cell surface properties, especially those pertaining to cell attachment/adhesion and aggregation behavior, can cause the microbe behavior to deviate from non-viable particles and hence greatly influence the mobility and distribution of microorganisms in porous media.This complexity highlights the need to obtain detailed information of cell-cell and cell-surface interactions in order to improve and refine the conceptual and quantitative model development for fate and transport of microorganisms and contaminant in subsurface. Traditional cell surface characterization methods are not sufficient to fully predict the deposition rates and transport behaviors of microorganism observed. A breakthrough of methodology that would allow for quantitative and molecular-level description of intrinsic cell surface properties indicative for cell

  18. IS Project Management and Risk Escalation: Towards A Dynamic Model

    Directory of Open Access Journals (Sweden)

    Angela Y Lin

    2015-03-01

    Full Text Available While the number of substantive investments in IS projects continues to grow, the number of failing projects also continues to increase at an alarming rate. Both the academic and industry literature suggests that inadequate attention to risk and its management continues to be a key factor in project failure. The typical approach taken is to identify and map potential risks, to act as a planning and diagnostic tool, and to prepare a contingency plan has been a factor-based approach. While it remains a valuable tool for mapping anticipated risks the factor-based approach is less effective when viewing project risks as emergent phenomena that un-fold during the course of the project, and require ongoing attention and risk management. In-formed by a case study of a failing university IS development project, this paper focuses on the phenomenon of risk escalation. The case findings suggest that rather than being defined ahead of the project, some project risks may emerge during the project as a consequence of escalation factors that were both antecedent to and a consequence of actual risk management decisions. The article concludes with suggestions as to how project managers can better man-age the emergent rather than static nature of risk phenomena.

  19. Dose escalation studies with caspofungin against Candida glabrata.

    Science.gov (United States)

    Domán, Marianna; Kovács, Renátó; Perlin, David S; Kardos, Gábor; Gesztelyi, Rudolf; Juhász, Béla; Bozó, Aliz; Majoros, László

    2015-09-01

    Echinocandins are recommended as first-line agents against invasive fungal infections caused by Candida glabrata, which still carry a high mortality rate. Dose escalation of echinocandins has been suggested to improve the clinical outcome against C. glabrata. To address this possibility, we performed in vitro and in vivo experiments with caspofungin against four WT C. glabrata clinical isolates, a drug-susceptible ATCC 90030 reference strain and two echinocandin-resistant strains with known FKS mutations. MIC values for the clinical isolates in RPMI 1640 were ≤ 0.03 mg l(-1 ) but increased to 0.125-0.25 mg l(-1 )in RPMI 1640+50% serum. In RPMI 1640+50% serum, the replication of C. glabrata was weaker than in RPMI 1640.Caspofungin in RPMI 1640 at 1 and 4 mg l(-1) showed a fungicidal effect within 7 h against three of the four clinical isolates but was only fungistatic at 16 and 32 mg l(-1) (paradoxically decreased killing activity). In RPMI 1640+50% serum, caspofungin at ≥ 1 mg l(-1) was rapidly fungicidal (within 3.31 h) against three of the four isolates. In a profoundly neutropenic murine model, all caspofungin doses (1, 2, 3, 5 and 20 mg kg(-1) daily) decreased the fungal tissue burdens significantly (P caspofungin dose escalation does not improve efficacy.

  20. Strategy for stochastic dose-rate induced enhanced elimination of malignant tumour without dose escalation.

    Science.gov (United States)

    Paul, Subhadip; Roy, Prasun Kumar

    2016-09-01

    The efficacy of radiation therapy, a primary modality of cancer treatment, depends in general upon the total radiation dose administered to the tumour during the course of therapy. Nevertheless, the delivered radiation also irradiates normal tissues and dose escalation procedure often increases the elimination of normal tissue as well. In this article, we have developed theoretical frameworks under the premise of linear-quadratic-linear (LQL) model using stochastic differential equation and Jensen's inequality for exploring the possibility of attending to the two therapeutic performance objectives in contraposition-increasing the elimination of prostate tumour cells and enhancing the relative sparing of normal tissue in fractionated radiation therapy, within a prescribed limit of total radiation dose. Our study predicts that stochastic temporal modulation in radiation dose-rate appreciably enhances prostate tumour cell elimination, without needing dose escalation in radiation therapy. However, constant higher dose-rate can also enhance the elimination of tumour cells. In this context, we have shown that the sparing of normal tissue with stochastic dose-rate is considerably more than the sparing of normal tissue with the equivalent constant higher dose-rate. Further, by contrasting the stochastic dose-rate effects under LQL and linear-quadratic (LQ) models, we have also shown that the LQ model over-estimates stochastic dose-rate effect in tumour and under-estimates the stochastic dose-rate effect in normal tissue. Our study indicates the possibility of utilizing stochastic modulation of radiation dose-rate for designing enhanced radiation therapy protocol for cancer.

  1. Controlling solution-phase polymer aggregation with molecular weight and solvent additives to optimize polymer-fullerene bulk heterojunction solar cells

    KAUST Repository

    Bartelt, Jonathan A.

    2014-03-20

    The bulk heterojunction (BHJ) solar cell performance of many polymers depends on the polymer molecular weight (M n) and the solvent additive(s) used for solution processing. However, the mechanism that causes these dependencies is not well understood. This work determines how M n and solvent additives affect the performance of BHJ solar cells made with the polymer poly(di(2-ethylhexyloxy)benzo[1,2-b:4,5-b\\']dithiophene-co- octylthieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD). Low M n PBDTTPD devices have exceedingly large fullerene-rich domains, which cause extensive charge-carrier recombination. Increasing the M n of PBDTTPD decreases the size of these domains and significantly improves device performance. PBDTTPD aggregation in solution affects the size of the fullerene-rich domains and this effect is linked to the dependency of PBDTTPD solubility on M n. Due to its poor solubility high M n PBDTTPD quickly forms a fibrillar polymer network during spin-casting and this network acts as a template that prevents large-scale phase separation. Furthermore, processing low M n PBDTTPD devices with a solvent additive improves device performance by inducing polymer aggregation in solution and preventing large fullerene-rich domains from forming. These findings highlight that polymer aggregation in solution plays a significant role in determining the morphology and performance of BHJ solar cells. The performance of poly(di(2-ethylhexyloxy) benzo[1,2-b:4,5-b\\']dithiophene-co-octylthieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD) bulk heterojunction solar cells strongly depends on the polymer molecular weight, and processing these bulk heterojunctions with a solvent additive preferentially improves the performance of low molecular weight devices. It is demonstrated that polymer aggregation in solution significantly impacts the thin-film bulk heterojunction morphology and is vital for high device performance. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Bromelain proteases reduce human platelet aggregation in vitro, adhesion to bovine endothelial cells and thrombus formation in rat vessels in vivo.

    Science.gov (United States)

    Metzig, C; Grabowska, E; Eckert, K; Rehse, K; Maurer, H R

    1999-01-01

    The thiol protease, bromelain, an extract from pineapple stem, was suggested to have antithrombotic and anticoagulant activities in vivo. We studied the effects of bromelain on cell size distribution of isolated human platelets in vitro by Coulter Counter measurements. Preincubation of platelets with bromelain (10 micrograms/mL) completely prevented the thrombin (0.2 U/mL) induced platelet aggregation. Papain was less active in preventing platelet aggregation. In vitro, bromelain (0.1 microgram/mL) reduced the adhesion of bound, thrombin stimulated, fluorescent labeled platelets to bovine aorta endothelial cells. In addition, preincubation of platelets with bromelain, prior to thrombin, activation, reduced the platelet adhesion to the endothelial cells to the low binding value of unstimulated platelets. On the basis of mass concentrations, the proteases papain and trypsin were as effective as bromelain. Using a laser thrombosis model, the in vivo effects of orally and intraveneously applied bromelain on thrombus formation in rat mesenteric vessels were studied. Bromelain, orally applied at 60 mg/kg body weight, inhibited the thrombus formation in a time dependent manner, the maximum being after 2 hours in 11% of arterioles and 6% of venoles. Intravenous application at 30 mg/kg was slightly more active in reducing thrombus formation in arterioles (13%) and venoles (5%), suggesting that orally applied bromelain is biologically active. These results may help to explain some of the clinical effects observed after bromelain treatment in patients with thrombosis and related diseases.

  3. Purification of the major outer membrane protein of Azospirillum brasilense, its affinity to plant roots, and its involvement in cell aggregation.

    Science.gov (United States)

    Burdman, S; Dulguerova, G; Okon, Y; Jurkevitch, E

    2001-04-01

    The major outer membrane protein (MOMP) of the nitrogen-fixing rhizobacterium Azospirillum brasilense strain Cd was purified and isolated by gel filtration, and antiserum against this protein was obtained. A screening of the binding of outer membrane proteins (OMPs) of A. brasilense to membrane-immobilized root extracts of various plant species revealed different affinities for the MOMP, with a stronger adhesion to extracts of cereals in comparison with legumes and tomatoes. Moreover, this protein was shown to bind to roots of different cereal seedlings in an in vitro adhesion assay. Incubation of A. brasilense cells with MOMP-antiserum led to fast agglutination, indicating that the MOMP is a surface-exposed protein. Cells incubated with Fab fragments obtained from purified MOMP-antiserum immunoglobulin G exhibited significant inhibition of bacterial aggregation as compared with controls. Bacteria preincubated with Fab fragments showed weaker adhesion to corn roots in comparison to controls without Fab fragments. These findings suggest that the A. brasilense MOMP acts as an adhesin involved in root adsorption and cell aggregation of this bacterium.

  4. The role of motivation, responsibility, and integrative complexity in crisis escalation: comparative studies of war and peace crises.

    Science.gov (United States)

    Winter, David G

    2007-05-01

    Drawing on D. G. Winter's (1993) comparison of 1914 and the Cuban Missile Crisis, the author identified 8 paired crises (1 escalating to war, 1 peacefully resolved). Documents (diplomatic messages, speeches, official media commentary) from each crisis were scored for power, affiliation, and achievement motivation; text measures of responsibility and activity inhibition; and integrative complexity. Aggregated effect-size results show that war crises had significantly higher levels of power motivation and responsibility, whereas peace crises showed trends toward higher integrative complexity and achievement motivation. Follow-up analyses suggested that these results are robust with respect to both sides in a crisis, type of material scored, and historical time. The power motive results extend previous findings, but the responsibility results suggest that responsibility plays a paradoxical role in war. Future research directions are sketched, and the role of psychological content analysis in monitoring the danger of war is discussed.

  5. Natural killer cell activity, lymphocyte proliferation, and cytokine profile in tumor-bearing mice treated with MAPA, a magnesium aggregated polymer from Aspergillus oryzae.

    Science.gov (United States)

    Justo, G Z; Durán, N; Queiroz, M L S

    2003-08-01

    The present study examined the effects of MAPA, an antitumor aggregated polymer of protein magnesium ammonium phospholinoleate-palmitoleate anhydride, isolated from Aspergillus oryzae, on concanavalin A (Con A)-induced spleen cell proliferation, cytokine production and on natural killer (NK) cell activity in Ehrlich ascites tumor-bearing mice. The Ehrlich ascites tumor (EAT) growth led to diminished mitogen-induced expansion of spleen cell populations and total NK activity. This was accompanied by striking spleen enlargement, with a marked increase in total cell counts. Moreover, a substantial enhancement in IL-10 levels, paralleled by a significant decrease in IL-2 was observed, while production of IL-4 and interferon-gamma (IFN-gamma) was not altered. Treatment of mice with 5 mg/kg MAPA for 7 days promoted spleen cell proliferation, IL-2 production and NK cell activity regardless of tumor outgrowth. In addition, MAPA treatment markedly enhanced IFN-gamma levels and reduced IL-10 production relative to EAT mice. A 35% reduction in splenomegaly with normal number of nucleated cells was also found. Altogether, our results suggest that MAPA directly and/or indirectly modulates immune cell activity, and probably disengages tumor-induced suppression of these responses. Clearly, MAPA has an impact and may delay tumor outgrowth through immunotherapeutic mechanisms.

  6. Reinjury risk of nano-calcium oxalate monohydrate and calcium oxalate dihydrate crystals on injured renal epithelial cells: aggravation of crystal adhesion and aggregation

    Directory of Open Access Journals (Sweden)

    Gan QZ

    2016-06-01

    , and cell death rate increased.Conclusion: Cell injury contributes to crystal adhesion to Vero cell surface. The attached nano-COM and COD crystals can aggravate Vero cell injury. As a consequence, crystal adhesion and aggregation are enhanced. These findings provide further insights into kidney stone formation. Keywords: nano-calcium oxalate crystals, cell injury, crystal adhesion, kidney stones

  7. Standardization of lyophilization medium for Streptococcus thermophilus subjected to viability escalation on freeze drying

    Directory of Open Access Journals (Sweden)

    Rohit Sharma

    2014-09-01

    Full Text Available The objective of the present study is to develop a lyophilization medium for Streptococcus thermophilus (NCIM 2904 as the industrial exploitation of this bacterium totally depends upon preservation and lyophilization protocols. Protective effect of 18 compounds were observed individually and in combinations with different sugars, sugar alcohols, polymers, protein concentrates and buffers. Among all the protectants tested, ammonium citrate (1% w/w, K2HPO4 (1% w/w and KH2PO4 (1% w/w provided lowest protection to these bacterial cells while 10% (w/w sodium caseinate, whey protein concentrate, sweet whey powder, and skim milk showed significant results in viability escalation. Survival in carbon sources like lactose, sucrose and maltodextrine was also favored maximally. Combination of sodium caseinate 10%, skim milk 5%, sucrose 5%, lactose 5% and mono sodium glutamate 1% in distilled water in ratio of 1:5 with S. thermophilus showed survival percentage of 96%.

  8. Riding the Escalator: How Dangerous is it Really?

    Directory of Open Access Journals (Sweden)

    Louisa H. Schminke

    2013-03-01

    Full Text Available Introduction: About 10,000 escalator-related injuries per year result in emergency departmenttreatment in the United States. Since the 1990s, a steady increase has been reported, but fewstatistics on escalator-related injuries have been published worldwide. We have therefore analyzedescalator accident statistics in admissions to our hospital in Switzerland since 2000.Methods: Using retrospective electronic patient chart analysis, we included in our study patients>16 years treated over an 11-year period. We categorized patients in terms of gender, age andassociated risk factors, and classified accidents according to day, time, location and cause. Resultingtrauma was categorized according to type and location. We divided post-admission treatment intosurgical and conservative, and into treatment as an outpatient, in a short-stay unit, or as a hospitaladmission. Women and men were compared using Fisher’s exact test.Results: We identified 173 patients with 285 discrete injuries. Of these, 87 patients (50% werewomen. Fifty-three (61% of the women and 38 (44% of the men were >60 years old (P = 0.033.Fifty percent of the men (43/86of the men, but only 7% (6/87 of the women showed signs of alcoholintoxication (P < 0.0001. Accidents in women occurred predominantly on Tuesdays (19/87; 22%between 12PM and 6PM (35/87; 40%, and in men on Saturdays (16/86; 19% between 6PM and12AM (29/86; 34%; P = 0.0097. Sixty-two percent (44/71 of the accidents were in public transportfacilities and 30% (21/71 in shopping centers. The majority of injuries in women were to the lowerextremities (49/87; 56%, while most accidents in men were to the head and neck (51/86; 59%; P =0.0052. About half (90; 52% of the patients were treated conservatively. Almost half of all patients(76, 44% required hospital admission. Of those, 45% left the hospital within 24 hours of admission(short stay unit and 55% stayed longer than 24 hours.Conclusion: Escalator accidents can result in severe

  9. Arginine–glycine–aspartic acid–polyethylene glycol–polyamidoamine dendrimer conjugate improves liver-cell aggregation and function in 3-D spheroid culture

    Directory of Open Access Journals (Sweden)

    Chen Z

    2016-08-01

    Full Text Available Zhanfei Chen,1,* Fen Lian,1,* Xiaoqian Wang,1 Yanling Chen,1,2 Nanhong Tang1,2 1Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, 2Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Research Center for Molecular Medicine, Fujian Medical University, Fuzhou, People’s Republic of China *These authors contributed equally to this work Abstract: The polyamidoamine (PAMAM dendrimer, a type of macromolecule material, has been used in spheroidal cell culture and drug delivery in recent years. However, PAMAM is not involved in the study of hepatic cell-spheroid culture or its biological activity, particularly in detoxification function. Here, we constructed a PAMAM-dendrimer conjugate decorated by an integrin ligand: arginine–glycine–aspartic acid (RGD peptide. Our studies demonstrate that RGD–polyethylene glycol (PEG–PAMAM conjugates can promote singly floating hepatic cells to aggregate together in a sphere-like growth with a weak reactive oxygen species. Moreover, RGD-PEG-PAMAM conjugates can activate the AKT–MAPK pathway in hepatic cells to promote cell proliferation and improve basic function and ammonia metabolism. Together, our data support the hepatocyte sphere treated by RGD-PEG-PAMAM conjugates as a potential source of hepatic cells for a biological artificial liver system. Keywords: dendrimer, arginine–glycine–aspartic acid (RGD, liver cell, spheroid culture, ammonia metabolism

  10. Increasing Use of Dose-Escalated External Beam Radiation Therapy for Men With Nonmetastatic Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Swisher-McClure, Samuel, E-mail: Swisher-Mcclure@uphs.upenn.edu [Department of Radiation Oncology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA (United States); Leonard Davis Institute of Health Economics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA (United States); Mitra, Nandita; Woo, Kaitlin [Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania (United States); Smaldone, Marc; Uzzo, Robert [Division of Urologic Oncology, Department of Surgery, Fox Chase Cancer Center, Temple University Health System, Philadelphia, PA (United States); Bekelman, Justin E. [Department of Radiation Oncology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA (United States); Leonard Davis Institute of Health Economics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA (United States); Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania (United States); Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania (United States)

    2014-05-01

    Purpose: To examine recent practice patterns, using a large national cancer registry, to understand the extent to which dose-escalated external beam radiation therapy (EBRT) has been incorporated into routine clinical practice for men with prostate cancer. Methods and Materials: We conducted a retrospective observational cohort study using the National Cancer Data Base, a nationwide oncology outcomes database in the United States. We identified 98,755 men diagnosed with nonmetastatic prostate cancer between 2006 and 2011 who received definitive EBRT and classified patients into National Comprehensive Cancer Network (NCCN) risk groups. We defined dose-escalated EBRT as total prescribed dose of ≥75.6 Gy. Using multivariable logistic regression, we examined the association of patient, clinical, and demographic characteristics with the use of dose-escalated EBRT. Results: Overall, 81.6% of men received dose-escalated EBRT during the study period. The use of dose-escalated EBRT did not vary substantially by NCCN risk group. Use of dose-escalated EBRT increased from 70.7% of patients receiving treatment in 2006 to 89.8% of patients receiving treatment in 2011. On multivariable analysis, year of diagnosis and use of intensity modulated radiation therapy were significantly associated with receipt of dose-escalated EBRT. Conclusions: Our study results indicate that dose-escalated EBRT has been widely adopted by radiation oncologists treating prostate cancer in the United States. The proportion of patients receiving dose-escalated EBRT increased nearly 20% between 2006 and 2011. We observed high utilization rates of dose-escalated EBRT within all disease risk groups. Adoption of intensity modulated radiation therapy was strongly associated with use of dose-escalated treatment.

  11. Awa1p on the cell surface of sake yeast inhibits biofilm formation and the co-aggregation between sake yeasts and Lactobacillus plantarum ML11-11.

    Science.gov (United States)

    Hirayama, Satoru; Shimizu, Masashi; Tsuchiya, Noriko; Furukawa, Soichi; Watanabe, Daisuke; Shimoi, Hitoshi; Takagi, Hiroshi; Ogihara, Hirokazu; Morinaga, Yasushi

    2015-05-01

    We examined mixed-species biofilm formation between Lactobacillus plantarum ML11-11 and both foaming and non-foaming mutant strains of Saccharomyces cerevisiae sake yeasts. Wild-type strains showed significantly lower levels of biofilm formation compared with the non-foaming mutants. Awa1p, a protein involved in foam formation during sake brewing, is a glycosylphosphatidylinositol (GPI)-anchored protein and is associated with the cell wall of sake yeasts. The AWA1 gene of the non-foaming mutant strain Kyokai no. 701 (K701) has lost the C-terminal sequence that includes the GPI anchor signal. Mixed-species biofilm formation and co-aggregation of wild-type strain Kyokai no. 7 (K7) were significantly lower than K701 UT-1 (K701 ura3/ura3 trp1/trp1), while the levels of strain K701 UT-1 carrying the AWA1 on a plasmid were comparable to those of K7. The levels of biofilm formation and co-aggregation of the strain K701 UT-1 harboring AWA1 with a deleted GPI anchor signal were similar to those of K701 UT-1. These results clearly demonstrate that Awa1p present on the surface of sake yeast strain K7 inhibits adhesion between yeast cells and L. plantarum ML11-11, consequently impeding mixed-species biofilm formation.

  12. Training Tolerance to Delay Using the Escalating Interest Task.

    Science.gov (United States)

    Rung, Jillian M; Young, Michael E

    2014-09-01

    The present study examined the lasting effects of exposure to reinforcement that increased in magnitude as a function of time between responses in a first-person shooter video game preparation of the escalating interest task. When reinforcement density increased as a function of time, it encouraged participants to wait longer between responses (shots of a weapon). Participants exposed to such contingencies waited significantly longer to fire their weapons than participants who were exposed to linear growth, where long inter-response times were not differentially reinforced. Those with experience in conditions where reinforcement density increased as a function of time showed persistently longer wait times when the contingencies changed in the latter portion of the game where the disincentive to fire quickly was removed. The potential utility of such contingencies for training tolerance to delay of reinforcement and the broader implications of training self-control are discussed.

  13. Factors associated with escalation and problematic approaches toward public figures.

    Science.gov (United States)

    Meloy, J Reid; James, David V; Mullen, Paul E; Pathé, Michele T; Farnham, Frank R; Preston, Lulu F; Darnley, Brian J

    2011-01-01

    Detailed comparison of factors associated with abnormal approach to the prominent and with escalation from communication to approach has not hitherto been undertaken. This partially reflects the failure of individual studies to adopt compatible terminologies. This study involves a careful dissection of six public figure studies, three involving U.S. politicians, two Hollywood celebrities, and one the British Royal Family. Common findings were unearthed across six headings. Approachers were significantly more likely to exhibit serious mental illness, engage in multiple means of communication, involve multiple contacts/targets, and to incorporate into their communication requests for help. They were significantly less likely to use threatening or antagonistic language in their communications, except in those cases involving security breaches. These results emphasize the importance of integrating mental health findings and preventive measures into risk management. Approach should not be regarded as a single behavioral category and has multiple motivations. Future studies should adopt standard terminology, preferably taken from the general stalking research.

  14. The Integrated Web Portal for Escalation with Overdose Control (EWOC).

    Science.gov (United States)

    Wang, Haibin; Tighiouart, Mourad; Huang, Shao-Chi; Berel, Dror; Cook-Wiens, Galen; Bresee, Catherine; Li, Quanlin; Rogatko, André

    2013-01-01

    In this paper, we present the design and implementation of a novel web portal for the cancer phase I clinical trial design method Escalation with Overdose Control (EWOC). The web portal has two major components: a web-based dose finding calculator; and a standalone and downloadable dose finding software which can be installed on Windows operating systems. The web-based dose finding calculator uses industry standards and is a database-driven and distributed computing platform for designing and conducting dose finding in cancer phase I clinical trials utilizing EWOC methodology. The web portal is developed using open source software: PHP, JQuery, R and OpenBUGS. It supports any standard browsers with internet connection. The web portal can be accessed at: http://biostatistics.csmc.edu.

  15. Do Sell-Side Stock Analysts Exhibit Escalation of Commitment?

    Science.gov (United States)

    Beshears, John; Milkman, Katherine L

    2011-03-01

    This paper presents evidence that when an analyst makes an out-of-consensus forecast of a company's quarterly earnings that turns out to be incorrect, she escalates her commitment to maintaining an out-of-consensus view on the company. Relative to an analyst who was close to the consensus, the out-of-consensus analyst adjusts her forecasts for the current fiscal year's earnings less in the direction of the quarterly earnings surprise. On average, this type of updating behavior reduces forecasting accuracy, so it does not seem to reflect superior private information. Further empirical results suggest that analysts do not have financial incentives to stand by extreme stock calls in the face of contradictory evidence. Managerial and financial market implications are discussed.

  16. Aggregation of Ribosomal Protein S6 at Nucleolus Is Cell Cycle-Controlled and Its Function in Pre-rRNA Processing Is Phosphorylation Dependent.

    Science.gov (United States)

    Zhang, Duo; Chen, Hui-Peng; Duan, Hai-Feng; Gao, Li-Hua; Shao, Yong; Chen, Ke-Yan; Wang, You-Liang; Lan, Feng-Hua; Hu, Xian-Wen

    2016-07-01

    Ribosomal protein S6 (rpS6) has long been regarded as one of the primary r-proteins that functions in the early stage of 40S subunit assembly, but its actual role is still obscure. The correct forming of 18S rRNA is a key step in the nuclear synthesis of 40S subunit. In this study, we demonstrate that rpS6 participates in the processing of 30S pre-rRNA to 18S rRNA only when its C-terminal five serines are phosphorylated, however, the process of entering the nucleus and then targeting the nucleolus does not dependent its phosphorylation. Remarkably, we also find that the aggregation of rpS6 at the nucleolus correlates to the phasing of cell cycle, beginning to concentrate in the nucleolus at later S phase and disaggregate at M phase. J. Cell. Biochem. 117: 1649-1657, 2016. © 2015 Wiley Periodicals, Inc.

  17. 42 CFR 405.1108 - MAC actions when request for review or escalation is filed.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false MAC actions when request for review or escalation...) Medicare Appeals Council Review § 405.1108 MAC actions when request for review or escalation is filed. (a) Except as specified in paragraphs (c) and (d) of this section, when a party requests that the MAC...

  18. Understanding the Emotional Aspects of Escalation of Commitment: The Role of Negative Affect

    Science.gov (United States)

    Wong, Kin Fai Ellick; Yik, Michelle; Kwong, Jessica Y. Y.

    2006-01-01

    Despite the importance of understanding the emotional aspects of organizational decision making, prior research has paid scant attention to the role of emotion in escalation of commitment. This article attempts to fill this gap by examining the relationship between negative affect and escalation of commitment. Results showed that regardless of…

  19. Attribution Bias and Overconfidence in Escalation of Commitment: The Role of Desire to Rectify Past Outcomes

    Science.gov (United States)

    Tine, Delilah Castillo

    2013-01-01

    Escalation of commitment is the voluntary continuation of investing resources into what appears to be a failing course of action whose outcome is uncertain. Investigation into the escalation of commitment phenomenon is important to organizations because such behavior could result in grave economic loss. This research investigates two cognitive…

  20. Role of multicellular aggregates in biofilm formation

    DEFF Research Database (Denmark)

    Kragh, Kasper N.; Hutchison, Jaime B.; Melaugh, Gavin;

    2016-01-01

    response, may add to this ecological benefit. Our findings suggest that current models of biofilm formation should be reconsidered to incorporate the role of aggregates in biofilm initiation.IMPORTANCE During the past decades, there has been a consensus around the model of development of a biofilm......In traditional models of in vitro biofilm development, individual bacterial cells seed a surface, multiply, and mature into multicellular, three-dimensional structures. Much research has been devoted to elucidating the mechanisms governing the initial attachment of single cells to surfaces. However......, in natural environments and during infection, bacterial cells tend to clump as multicellular aggregates, and biofilms can also slough off aggregates as a part of the dispersal process. This makes it likely that biofilms are often seeded by aggregates and single cells, yet how these aggregates impact biofilm...

  1. A comparison between gray and white mineral trioxide aggregate (MTA and calcium enriched mixture (CEM cytotoxicity in L929 and Saos-2 cell lines

    Directory of Open Access Journals (Sweden)

    Robab Farhang

    2016-12-01

    Full Text Available The purpose was to compare the cytotoxic effects of two commonly used mineral trioxide aggregate (MTA (gray & white with the recently introduced calcium enriched mixture (CEM in L929 and Saos-2 cell lines and to determine the oxidative stressinduced by each cement. Sterile discs of each cement were submerged and incubated in complete media for 24, 48 and 72-h. The cell lines were exposed to two fold serial dilutions (1, 0.5, 0.25 X of each extract. In addition to trypan blue (TB dye exclusion test, MTT assay was carried out after 24-h. To determine the oxidative stress mediated cell toxicity, malondialdehyde (MDA concentration and total ferric reduction activity potential (FRAP were measured in the media.The MTT and TB results with 48-h and 72-h CEM extracts showed that both extracts are cytotoxic in L929 cell line at 1 X and 0.5 X dilutions, while neither white MTA (WMTA nor gray MTA (GMTA showed any toxic effects in this cell line. On the other hand all three cements (undiluted 48-h and 72-h extracts were cytotoxic against Saos-2 cell line. The oxidative stress marker (MDA was proportionate to the cytotoxic effects of CEM while there was no significant changes in reductive capacity of the media measured by FRAP in both cell lines.The cytotoxic effects of CEM on L929 and Saos-2 cell lines seems to be higher than WMTA and GMTA and it is increased by the time of extraction up to 72-h.. However, CEM, WMTA and GMTA showed similar toxic effect in Saos-2 cell line proportionate to the oxidative stress measured by TBARS. It seems that while all three cements extracts don't change the antioxidant activity of the media, they could significantly increase lipid peroxidation, especially CEM with Saos-2 cell line which elucidate triggering oxidative stress mechanisms without having direct oxidative activity.

  2. Inherently irrational? A computational model of escalation of commitment as Bayesian Updating.

    Science.gov (United States)

    Gilroy, Shawn P; Hantula, Donald A

    2016-06-01

    Monte Carlo simulations were performed to analyze the degree to which two-, three- and four-step learning histories of losses and gains correlated with escalation and persistence in extended extinction (continuous loss) conditions. Simulated learning histories were randomly generated at varying lengths and compositions and warranted probabilities were determined using Bayesian Updating methods. Bayesian Updating predicted instances where particular learning sequences were more likely to engender escalation and persistence under extinction conditions. All simulations revealed greater rates of escalation and persistence in the presence of heterogeneous (e.g., both Wins and Losses) lag sequences, with substantially increased rates of escalation when lags comprised predominantly of losses were followed by wins. These methods were then applied to human investment choices in earlier experiments. The Bayesian Updating models corresponded with data obtained from these experiments. These findings suggest that Bayesian Updating can be utilized as a model for understanding how and when individual commitment may escalate and persist despite continued failures.

  3. Escalation research: providing new frontiers for applying behavior analysis to organizational behavior.

    Science.gov (United States)

    Goltz, S M

    2000-01-01

    Decision fiascoes such as escalation of commitment, the tendency of decision makers to "throw good money after bad," can have serious consequences for organizations and are therefore of great interest in applied research. This paper discusses the use of behavior analysis in organizational behavior research on escalation. Among the most significant aspects of behavior-analytic research on escalation is that it has indicated that both the patterns of outcomes that decision makers have experienced for past decisions and the patterns of responses that they make are critical for understanding escalation. This research has also stimulated the refinement of methods by researchers to better assess decision making and the role reinforcement plays in it. Finally, behavior-analytic escalation research has not only indicated the utility of reinforcement principles for predicting more complex human behavior but has also suggested some additional areas for future exploration of decision making using behavior analysis.

  4. CD40-induced aggregation of MHC class II and CD80 on the cell surface leads to an early enhancement in antigen presentation.

    Science.gov (United States)

    Clatza, Abigail; Bonifaz, Laura C; Vignali, Dario A A; Moreno, José

    2003-12-15

    Ligation of CD40 on B cells increases their ability to present Ag and to activate MHC class II (MHC-II)-restricted T cells. How this occurs is not entirely clear. In this study we demonstrate that CD40 ligation on Ag-presenting B cells (APC) for a short period between 30 min and 3 h has a rapid, augmenting effect on the ability of a B cell line and normal B cells to activate T cells. This is not due to alterations in Ag processing or to an increase in surface expression of CD80, CD86, ICAM-1, or MHC-II. This effect is particularly evident with naive, resting T lymphocytes and appears to be more pronounced under limiting Ag concentrations. Shortly after CD40 ligation on a B cell line, MHC-II and CD80 progressively accumulated in cholesterol-enriched microdomains on the cell surface, which correlated with an initial enhancement in their Ag presentation ability. Moreover, CD40 ligation induced a second, late, more sustained enhancement of Ag presentation, which correlates with a significant increase in CD80 expression by APC. Thus, CD40 signaling enhances the efficiency with which APC activate T cells by at least two related, but distinct, mechanisms: an early stage characterized by aggregation of MHC-II and CD80 clusters, and a late stage in which a significant increase in CD80 expression is observed. These results raise the possibility that one important role of CD40 is to contribute to the formation of the immunological synapse on the APC side.

  5. THE CELLS WITH MYCOBACTERIA IN GRANULOMATOUS AGGREGATES FROM MICE WITH LATENT TUBERCULOUS INFECTION IN EX VIVO CULTURE

    Directory of Open Access Journals (Sweden)

    E. G. Ufimtseva

    2013-01-01

    Full Text Available Abstract. The aim of this study was to obtain ex vivo monolayer culture cells migrated from individual granulomas isolated from the spleens of the Balb/c line mice through 1–2 months after BCG vaccine infection. The second goal was to evaluate influence of different types of cells in the development of granulomatic inflammation and analysis of BCG bacteria content in these cells in the latent stage of tuberculosis. Granulomas were presented by macrophages in general. The number of granulomas was varied as in one mouse as between mice. Granulomas contained also dendritic cells (in average 10% from macrophages of granulomas and lymphocytes. In some granulomas fibroblasts, neutrophils, eosiniphils, multinuclear cells of Pirogov–Langhans, megacariocytes and platelets were observed in all stages of infection. The number of these cells was also varied between granulomas. The acid staining BCG bacteria were only detected in macrophages, dendritic cells and Pirogov–Langhans cells of mice granulomas. Mice were different as by number of cells with BCG bacteria in granulomas as by number of granulomas with BCG-containing cells. The proposed model of granuloma cells of mice in ex vivo culture can be used to study interaction between host cells and mycobacteria to find new ways and methods of influence to intracellular pathogens in latent stage of tuberculosis. 

  6. Cellular strategies for regulating functional and nonfunctional protein aggregation.

    Science.gov (United States)

    Gsponer, Jörg; Babu, M Madan

    2012-11-29

    Growing evidence suggests that aggregation-prone proteins are both harmful and functional for a cell. How do cellular systems balance the detrimental and beneficial effect of protein aggregation? We reveal that aggregation-prone proteins are subject to differential transcriptional, translational, and degradation control compared to nonaggregation-prone proteins, which leads to their decreased synthesis, low abundance, and high turnover. Genetic modulators that enhance the aggregation phenotype are enriched in genes that influence expression homeostasis. Moreover, genes encoding aggregation-prone proteins are more likely to be harmful when overexpressed. The trends are evolutionarily conserved and suggest a strategy whereby cellular mechanisms specifically modulate the availability of aggregation-prone proteins to (1) keep concentrations below the critical ones required for aggregation and (2) shift the equilibrium between the monomeric and oligomeric/aggregate form, as explained by Le Chatelier's principle. This strategy may prevent formation of undesirable aggregates and keep functional assemblies/aggregates under control.

  7. 77 FR 42353 - Escalate Capital Partners SBIC I, L.P.; Notice Seeking Exemption Under Section 312 of the Small...

    Science.gov (United States)

    2012-07-18

    ... ADMINISTRATION Escalate Capital Partners SBIC I, L.P.; Notice Seeking Exemption Under Section 312 of the Small Business Investment Act, Conflicts of Interest Notice is hereby given that Escalate Capital Partners SBIC I...). Escalate Capital Partners SBIC I, L.P. proposes to make a debt investment in Mavenir Systems, Inc.,...

  8. Molecular engineering of simple phenothiazine-based dyes to modulate dye aggregation, charge recombination, and dye regeneration in highly efficient dye-sensitized solar cells.

    Science.gov (United States)

    Hua, Yong; Chang, Shuai; He, Jian; Zhang, Caishun; Zhao, Jianzhang; Chen, Tao; Wong, Wai-Yeung; Wong, Wai-Kwok; Zhu, Xunjin

    2014-05-19

    A series of simple phenothiazine-based dyes, namely, TP, EP, TTP, ETP, and EEP have been developed, in which the thiophene (T), ethylenedioxythiophene (E), their dimers, and mixtures are present to modulate dye aggregation, charge recombination, and dye regeneration for highly efficient dye-sensitized solar cell (DSSC) applications. Devices sensitized by the dyes TP and TTP display high power conversion efficiencies (PCEs) of 8.07 (Jsc = 15.2 mA cm(-2), Voc =0.783 V, fill factor (FF) = 0.679) and 7.87 % (Jsc = 16.1 mA cm(-2), Voc = 0.717 V, FF = 0.681), respectively; these were measured under simulated AM 1.5 sunlight in conjunction with the I(-)/I3(-) redox couple. By replacing the T group with the E unit, EP-based DSSCs had a slightly lower PCE of 7.98 % with a higher short-circuit photocurrent (Jsc) of 16.7 mA cm(-2). The dye ETP, with a mixture of E and T, had an even lower PCE of 5.62 %. Specifically, the cell based on the dye EEP, with a dimer of E, had inferior Jsc and Voc values and corresponded to the lowest PCE of 2.24 %. The results indicate that the photovoltaic performance can be finely modulated through structural engineering of the dyes. The selection of T analogues as donors can not only modulate light absorption and energy levels, but also have an impact on dye aggregation and interfacial charge recombination of electrons at the interface of titania, electrolytes, and/or oxidized dye molecules; this was demonstrated through DFT calculations, electrochemical impedance analysis, and transient photovoltage studies.

  9. The nuclear lamina promotes telomere aggregation and centromere peripheral localization during senescence of human mesenchymal stem cells

    NARCIS (Netherlands)

    Raz, Vered; Vermolen, Bart J.; Garini, Yuval; Onderwater, Jos J.M.; Mommaas-Kienhuis, Mieke A.; Koster, Abraham J.; Young, Ian T.; Tanke, Hans; Dirks, Roeland W.

    2008-01-01

    Ex vivo, human mesenchymal stem cells (hMSCs) undergo spontaneous cellular senescence after a limited number of cell divisions. Intranuclear structures of the nuclear lamina were formed in senescent hMSCs, which are identified by the presence of Hayflick-senescence-associated factors. Notably, spati

  10. De-escalation, adequacy of antibiotic therapy and culture positivity in septic patients: an observational study

    Science.gov (United States)

    Moraes, Rafael Barberena; Guillén, Julián Alberto Viteri; Zabaleta, William Javier Castillo; Borges, Flavia Kessler

    2016-01-01

    Objective To evaluate the prevalence of antibiotic de-escalation in patients diagnosed with severe sepsis or septic shock at a public academic tertiary hospital and to evaluate antibiotic adequacy and culture positivity. Methods The prevalence of antibiotic de-escalation, the adequacy of antibiotic treatment and the rates of culture positivity were analyzed in patients with severe sepsis and septic shock between April and December 2013 at an intensive care unit in a tertiary university hospital. Results Among the 224 patients included in the study, de-escalation was appropriate in 66 patients (29.4%) but was implemented in 44 patients (19.6%). Among the patients who underwent de-escalation, half experienced narrowing of the antimicrobial spectrum. The mortality rate was 56.3%, with no differences between the patients with or without de-escalation (56.8% versus 56.1%; p = 0.999) nor in the length of hospital stay. Empirical antibiotic therapy was appropriate in 89% of cases. Microorganisms were isolated from total cultures in 30% of cases and from blood cultures in 26.3% of cases. Conclusion The adequacy rate of empirical antibiotic therapy was high, reflecting an active institutional policy of monitoring epidemiological profiles and institutional protocols on antimicrobial use. However, antibiotic de-escalation could have been implemented in a greater number of patients. De-escalation did not affect mortality rates. PMID:27626951

  11. Using optical profilometry to characterize cell membrane roughness influenced by amyloid-beta 42 aggregates and electric fields

    Science.gov (United States)

    Pan, Huei-Jyuan; Wang, Ruei-Lin; Xiao, Jian-Long; Chang, Yu-Jen; Cheng, Ji-Yen; Chen, Yun-Ru; Lee, Chau-Hwang

    2014-01-01

    The membrane roughness of Neuro-2a neroblastoma cells is measured by using noninterferometric wide-field optical profilometry. The cells are treated with the fibril and oligomer conformers of amyloid-beta (Aβ) 42, which is a peptide of 42 amino acids related to the development of Alzheimer's disease. We find that both the Aβ42 fibrils and Aβ42 oligomers reduced the cell membrane roughness, but the effect of Aβ42 oligomers was faster and stronger than that of the fibrils. We also apply direct-current electric field (dcEF) stimulations on the cells. A dcEF of 300 mV/mm can increase the membrane roughness under the treatment of Aβ42. These results suggest that Aβ42 can decrease the membrane compliance of live neuroblastoma cells, and dcEFs may counteract this effect.

  12. Verbal De-escalation of the Agitated Patient: Consensus Statement of the American Association for Emergency Psychiatry Project BETA De-escalation Workgroup.

    Science.gov (United States)

    Richmond, Janet S; Berlin, Jon S; Fishkind, Avrim B; Holloman, Garland H; Zeller, Scott L; Wilson, Michael P; Rifai, Muhamad Aly; Ng, Anthony T

    2012-02-01

    Agitation is an acute behavioral emergency requiring immediate intervention. Traditional methods of treating agitated patients, ie, routine restraints and involuntary medication, have been replaced with a much greater emphasis on a noncoercive approach. Experienced practitioners have found that if such interventions are undertaken with genuine commitment, successful outcomes can occur far more often than previously thought possible. In the new paradigm, a 3-step approach is used. First, the patient is verbally engaged; then a collaborative relationship is established; and, finally, the patient is verbally de-escalated out of the agitated state. Verbal de-escalation is usually the key to engaging the patient and helping him become an active partner in his evaluation and treatment; although, we also recognize that in some cases nonverbal approaches, such as voluntary medication and environment planning, are also important. When working with an agitated patient, there are 4 main objectives: (1) ensure the safety of the patient, staff, and others in the area; (2) help the patient manage his emotions and distress and maintain or regain control of his behavior; (3) avoid the use of restraint when at all possible; and (4) avoid coercive interventions that escalate agitation. The authors detail the proper foundations for appropriate training for de-escalation and provide intervention guidelines, using the "10 domains of de-escalation."

  13. The influence of toxicity constraints in models of chemotherapeutic protocol escalation

    KAUST Repository

    Boston, E. A. J.

    2011-04-06

    The prospect of exploiting mathematical and computational models to gain insight into the influence of scheduling on cancer chemotherapeutic effectiveness is increasingly being considered. However, the question of whether such models are robust to the inclusion of additional tumour biology is relatively unexplored. In this paper, we consider a common strategy for improving protocol scheduling that has foundations in mathematical modelling, namely the concept of dose densification, whereby rest phases between drug administrations are reduced. To maintain a manageable scope in our studies, we focus on a single cell cycle phase-specific agent with uncomplicated pharmacokinetics, as motivated by 5-Fluorouracil-based adjuvant treatments of liver micrometastases. In particular, we explore predictions of the effectiveness of dose densification and other escalations of the protocol scheduling when the influence of toxicity constraints, cell cycle phase specificity and the evolution of drug resistance are all represented within the modelling. For our specific focus, we observe that the cell cycle and toxicity should not simply be neglected in modelling studies. Our explorations also reveal the prediction that dose densification is often, but not universally, effective. Furthermore, adjustments in the duration of drug administrations are predicted to be important, especially when dose densification in isolation does not yield improvements in protocol outcomes. © The author 2011. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.

  14. Error Cost Escalation Through the Project Life Cycle

    Science.gov (United States)

    Stecklein, Jonette M.; Dabney, Jim; Dick, Brandon; Haskins, Bill; Lovell, Randy; Moroney, Gregory

    2004-01-01

    It is well known that the costs to fix errors increase as the project matures, but how fast do those costs build? A study was performed to determine the relative cost of fixing errors discovered during various phases of a project life cycle. This study used three approaches to determine the relative costs: the bottom-up cost method, the total cost breakdown method, and the top-down hypothetical project method. The approaches and results described in this paper presume development of a hardware/software system having project characteristics similar to those used in the development of a large, complex spacecraft, a military aircraft, or a small communications satellite. The results show the degree to which costs escalate, as errors are discovered and fixed at later and later phases in the project life cycle. If the cost of fixing a requirements error discovered during the requirements phase is defined to be 1 unit, the cost to fix that error if found during the design phase increases to 3 - 8 units; at the manufacturing/build phase, the cost to fix the error is 7 - 16 units; at the integration and test phase, the cost to fix the error becomes 21 - 78 units; and at the operations phase, the cost to fix the requirements error ranged from 29 units to more than 1500 units

  15. Dengue: an escalating public health problem in Latin America.

    Science.gov (United States)

    Tapia-Conyer, Roberto; Betancourt-Cravioto, Miguel; Méndez-Galván, Jorge

    2012-05-01

    Dengue infection is a significant and escalating public health problem in Latin America. Its re-emergence and subsequent rise in the region over the past 50 years has largely been caused by a combination of a lack of political will, the radical growth of urban populations, migration flow and insufficient financial resources. Its increased incidence has been compounded by climate change, poor sanitation and extreme poverty, which lead to more breeding sites of the mosquito vector Aedes aegypti. In order to control dengue effectively, an integrated approach incorporating vector management and environmental and social solutions is required. To achieve success, these programmes require commitment and responses at both national and community level. The development of a vaccine is a vital tool in the fight against dengue. For successful introduction, those implementing vaccination need to be educated on the value of such a strategy. Effective political leadership, innovative financial mechanisms and co-operation across all disciplines, sectors and national borders are essential to eradication of the disease.

  16. 3-D analysis of bacterial cell-(iron)mineral aggregates formed during Fe(II) oxidation by the nitrate-reducing Acidovorax sp. strain BoFeN1 using complementary microscopy tomography approaches.

    Science.gov (United States)

    Schmid, G; Zeitvogel, F; Hao, L; Ingino, P; Floetenmeyer, M; Stierhof, Y-D; Schroeppel, B; Burkhardt, C J; Kappler, A; Obst, M

    2014-07-01

    The formation of cell-(iron)mineral aggregates as a consequence of bacterial iron oxidation is an environmentally widespread process with a number of implications for processes such as sorption and coprecipitation of contaminants and nutrients. Whereas the overall appearance of such aggregates is easily accessible using 2-D microscopy techniques, the 3-D and internal structure remain obscure. In this study, we examined the 3-D structure of cell-(iron)mineral aggregates formed during Fe(II) oxidation by the nitrate-reducing Acidovorax sp. strain BoFeN1 using a combination of advanced 3-D microscopy techniques. We obtained 3-D structural and chemical information on different cellular encrustation patterns at high spatial resolution (4-200 nm, depending on the method): more specifically, (1) cells free of iron minerals, (2) periplasm filled with iron minerals, (3) spike- or platelet-shaped iron mineral structures, (4) bulky structures on the cell surface, (5) extracellular iron mineral shell structures, (6) cells with iron mineral filled cytoplasm, and (7) agglomerations of extracellular globular structures. In addition to structural information, chemical nanotomography suggests a dominant role of extracellular polymeric substances (EPS) in controlling the formation of cell-(iron)mineral aggregates. Furthermore, samples in their hydrated state showed cell-(iron)mineral aggregates in pristine conditions free of preparation (i.e., drying/dehydration) artifacts. All these results were obtained using 3-D microscopy techniques such as focused ion beam (FIB)/scanning electron microscopy (SEM) tomography, transmission electron microscopy (TEM) tomography, scanning transmission (soft) X-ray microscopy (STXM) tomography, and confocal laser scanning microscopy (CLSM). It turned out that, due to the various different contrast mechanisms of the individual approaches, and due to the required sample preparation steps, only the combination of these techniques was able to provide a

  17. Escalation scenarios initiated by gas explosions on offshore installations. Probabilistic cause and consequence modelling

    Energy Technology Data Exchange (ETDEWEB)

    Eknes, Monika Loeland

    1996-12-31

    This Dr. ing. thesis deals with escalation scenarios initiated by gas explosions on offshore installations. Gas explosions is one of the major hazards to such installations. The objectives were to estimate the probability of ignition and frequency of gas explosions for gas leaks on top sides of offshore installations, and to estimate the response and resistance of components that could result in escalation if they failed. Main fields considered cover risk analysis methodology, gas explosions, simplified escalation models, evaluation of structural consequences, case studies, and guidelines. 107 refs., 33 figs., 33 tabs.

  18. Platelet aggregation following trauma

    DEFF Research Database (Denmark)

    Windeløv, Nis A; Sørensen, Anne M; Perner, Anders

    2014-01-01

    We aimed to elucidate platelet function in trauma patients, as it is pivotal for hemostasis yet remains scarcely investigated in this population. We conducted a prospective observational study of platelet aggregation capacity in 213 adult trauma patients on admission to an emergency department (ED......). Inclusion criteria were trauma team activation and arterial cannula insertion on arrival. Blood samples were analyzed by multiple electrode aggregometry initiated by thrombin receptor agonist peptide 6 (TRAP) or collagen using a Multiplate device. Blood was sampled median 65 min after injury; median injury...... severity score (ISS) was 17; 14 (7%) patients received 10 or more units of red blood cells in the ED (massive transfusion); 24 (11%) patients died within 28 days of trauma: 17 due to cerebral injuries, four due to exsanguination, and three from other causes. No significant association was found between...

  19. Shaping the Growth Behaviour of Bacterial Aggregates in Biofilms

    CERN Document Server

    Melaugh, Gavin; Kragh, Kasper Nørskov; Irie, Yasuhiko; Roberts, Aled; Bjarnsholt, Thomas; Diggle, Steve P; Gordon, Vernita; Allen, Rosalind J

    2015-01-01

    Bacterial biofilms are usually assumed to originate from individual cells deposited on a surface. However, many biofilm-forming bacteria tend to aggregate in the planktonic phase meaning it is possible that many natural and infectious biofilms originate wholly or partially from pre-formed cell aggregates. Here, we use agent-based computer simulations to investigate the role of pre-formed aggregates in biofilm development. Focusing on the role of aggregate shape, we find that the degree of spreading of an aggregate on a surface can play a key role in determining its eventual fate during biofilm development. Specifically, initially spread aggregates perform better when competition with surrounding bacterial cells is low, while initially rounded aggregates perform better when competition is high. These contrasting outcomes are governed by a trade-off between aggregate surface area and height. Our results provide new insight into biofilm formation and development, and reveal new factors that may be at play in the...

  20. Controlled aggregation of primary human pancreatic islet cells leads to glucose-responsive pseudoislets comparable to native islets

    NARCIS (Netherlands)

    Hilderink, Janneke; Spijker, Siebe; Carlotti, Françoise; Lange, Lydia; Engelse, Marten; van Blitterswijk, Clemens; de Koning, Eelco; Karperien, Marcel; van Apeldoorn, Aart

    2015-01-01

    Clinical islet transplantation is a promising treatment for patients with type 1 diabetes. However, pancreatic islets vary in size and shape affecting their survival and function after transplantation because of mass transport limitations. To reduce diffusion restrictions and improve islet cell surv

  1. Inter-beat intervals of cardiac-cell aggregates during exposure to 2.45 GHz CW, pulsed, and square-wave-modulated microwaves.

    Science.gov (United States)

    Seaman, R L; DeHaan, R L

    1993-01-01

    Inter-beat intervals of aggregated cardiac cells from chicken embryos were studied during 190 s exposures to 2.45 GHz microwaves in an open-ended coaxial device. Averaged specific-absorption rates (SARs) and modulation conditions were 1.2-86.9 W/kg continuous-wave (CW), 1.2-12.2 W/kg pulse modulation (PW, duty cycle approximately 11%), and 12.0-43.5 W/kg square-wave modulation (duty cycle = 50%). The inter-beat interval decreased during microwave exposures at 42.0 W/kg and higher when CW or square-wave modulation was used, which is consistent with established effects of elevated temperatures. However, increases in the inter-beat interval during CW exposures at 1.2-12.2 W/kg, and decreases in the inter-beat interval after PW exposures at 8.4-12.2 W/kg, are not consistent with simple thermal effects. Analysis of variance indicated that SAR, modulation, and the modulation-SAR interaction were all significant factors in altering the inter-beat interval. The latter two factors indicated that the cardiac cells were affected by athermal as well as thermal effects of microwave exposure.

  2. Efficacy of imatinib dose escalation in Chinese gastrointestinal stromal tumor patients

    Institute of Scientific and Technical Information of China (English)

    Jian Li; Ji-Fang Gong; Jie Li; Jing Gao; Nai-Ping Sun; Lin Shen

    2012-01-01

    AIM:To investigate the efficacy and safety of imatinib dose escalation in Chinese patients with advanced gastrointestinal stromal tumor (GIST).METHODS:Advanced GIST patients previously failing 400 mg imatinib treatment were enrolled in this study.Patients received imatinib with dose escalation to 600mg/d,and further dose escalation to 800 mg/d if imatinib 600 mg/d failed.Progression-free survival,overall survival,clinical efficacy,c-kit/PDGFRA genotype and safety were evaluated.RESULTS:52 patients were enrolled in this study.For the 47 evaluable patients receiving imatinib (600 mg/d),the disease control rate was 40.4%,and the median progression-free survival for all patients was 17 wk (95% CI:3.9-30.1).The median overall survival after dose escalation was 81 wk (95% CI:36.2-125.8).Adverse events,mainly edema,fatigue,granulocytopenia and skin rash were tolerable.However,further dose escalation (800 mg/d) in 14 cases was ineffective,with disease progression and severe adverse events.Among 30 cases examined for gene mutations,patients with exon 9 mutations experienced a better progression-free survival of 47 wk.CONCLUSION:Imatinib dose escalation to 600 mg/d is more appropriate for Chinese patients and may achieve further survival benefit.

  3. Effects of Titanium Dioxide Nanoparticle Aggregate Size on Gene Expression

    Directory of Open Access Journals (Sweden)

    Junko Okuda-Shimazaki

    2010-06-01

    Full Text Available Titanium dioxide (titania nanoparticle aggregation is an important factor in understanding cytotoxicity. However, the effect of the aggregate size of nanoparticles on cells is unclear. We prepared two sizes of titania aggregate particles and investigated their biological activity by analyzing biomarker expression based on mRNA expression analysis. The aggregate particle sizes of small and large aggregated titania were 166 nm (PDI = 0.291 and 596 nm (PDI = 0.417, respectively. These two size groups were separated by centrifugation from the same initial nanoparticle sample. We analyzed the gene expression of biomarkers focused on stress, inflammation, and cytotoxicity. Large titania aggregates show a larger effect on cell viability and gene expression when compared with the small aggregates. This suggests that particle aggregate size is related to cellular effects.

  4. The P2Y2 receptor mediates uptake of matrix-retained and aggregated low density lipoprotein in primary vascular smooth muscle cells

    Science.gov (United States)

    Dissmore, Tixieanna; Seye, Cheikh I.; Medeiros, Denis M.; Weisman, Gary A.; Bardford, Barry; Mamedova, Laman

    2016-01-01

    Background and aims The internalization of aggregated low-density lipoproteins (agLDL) mediated by low-density lipoprotein receptor related protein (LRP1) may involve the actin cytoskeleton in ways that differ from the endocytosis of soluble LDL by the LDL receptor (LDLR). This study aims to define novel mechanisms of agLDL uptake through modulation of the actin cytoskeleton, to identify molecular targets involved in foam cell formation in vascular smooth muscle cells (VSMCs). The critical observation that formed the basis for these studies is that under pathophysiological conditions, nucleotide release from blood-derived and vascular cells activates SMC P2Y2 receptors (P2Y2Rs) leading to rearrangement of the actin cytoskeleton and cell motility. Therefore, we tested the hypothesis that P2Y2R activation mediates agLDL uptake by VSMCs. Methods Primary VSMCs were isolated from aortas of wild type (WT) C57BL/6 and.P2Y2R−/− mice to investigate whether P2Y2R activation modulates LRP1 expression. Cells were transiently transfected with cDNA encoding a hemagglutinin-tagged (HA-tagged) WT P2Y2R, or a mutant P2Y2R that unlike the WT P2Y2R does not bind the cytoskeletal actin-binding protein filamin-A (FLN-A). Results P2Y2R activation significantly increased agLDL uptake, and LRP1 mRNA expression decreased in P2Y2R−/− VSMCs versus WT. SMCs, expressing P2Y2R defective in FLN-A binding, exhibit 3-fold lower LDLR expression levels than SMCs expressing WT P2Y2R, while cells transfected with WT P2Y2R show greater agLDL uptake in both WT and P2Y2R−/− VSMCs versus cells transfected with the mutant P2Y2R. Conclusions Together, these results show that both LRP1 and LDLR expression and agLDL uptake are regulated by P2Y2R in VSMCs, and that agLDL uptake due to P2Y2R activation is dependent upon cytoskeletal reorganization mediated by P2Y2R binding to FLN-A. PMID:27522265

  5. Effect of the surfactant Tween 80 on the detachment and dispersal of Salmonella enterica Thompson single cells and aggregates from cilantro leaves as revealed by image analysis

    Science.gov (United States)

    Biofilms formed by human enteric pathogens on plants are a great concern to the produce industry. Salmonella enterica has the ability to form biofilms and large aggregates on leaf surfaces, including on cilantro leaves. Aggregates that remained attached after rigorous washing of cilantro leaves and ...

  6. Priming by chemokines restricts lateral mobility of the adhesion receptor LFA-1 and restores adhesion to ICAM-1 nano-aggregates on human mature dendritic cells.

    Directory of Open Access Journals (Sweden)

    Kyra J E Borgman

    Full Text Available LFA-1 is a leukocyte specific β2 integrin that plays a major role in regulating adhesion and migration of different immune cells. Recent data suggest that LFA-1 on mature dendritic cells (mDCs may function as a chemokine-inducible anchor during homing of DCs through the afferent lymphatics into the lymph nodes, by transiently switching its molecular conformational state. However, the role of LFA-1 mobility in this process is not yet known, despite that the importance of lateral organization and dynamics for LFA-1-mediated adhesion regulation is broadly recognized. Using single particle tracking approaches we here show that LFA-1 exhibits higher mobility on resting mDCs compared to monocytes. Lymphoid chemokine CCL21 stimulation of the LFA-1 high affinity state on mDCs, led to a significant reduction of mobility and an increase on the fraction of stationary receptors, consistent with re-activation of the receptor. Addition of soluble monomeric ICAM-1 in the presence of CCL21 did not alter the diffusion profile of LFA-1 while soluble ICAM-1 nano-aggregates in the presence of CCL21 further reduced LFA-1 mobility and readily bound to the receptor. Overall, our results emphasize the importance of LFA-1 lateral mobility across the membrane on the regulation of integrin activation and its function as adhesion receptor. Importantly, our data show that chemokines alone are not sufficient to trigger the high affinity state of the integrin based on the strict definition that affinity refers to the adhesion capacity of a single receptor to its ligand in solution. Instead our data indicate that nanoclustering of the receptor, induced by multi-ligand binding, is required to maintain stable cell adhesion once LFA-1 high affinity state is transiently triggered by inside-out signals.

  7. Priming by chemokines restricts lateral mobility of the adhesion receptor LFA-1 and restores adhesion to ICAM-1 nano-aggregates on human mature dendritic cells.

    Science.gov (United States)

    Borgman, Kyra J E; van Zanten, Thomas S; Manzo, Carlo; Cabezón, Raquel; Cambi, Alessandra; Benítez-Ribas, Daniel; Garcia-Parajo, Maria F

    2014-01-01

    LFA-1 is a leukocyte specific β2 integrin that plays a major role in regulating adhesion and migration of different immune cells. Recent data suggest that LFA-1 on mature dendritic cells (mDCs) may function as a chemokine-inducible anchor during homing of DCs through the afferent lymphatics into the lymph nodes, by transiently switching its molecular conformational state. However, the role of LFA-1 mobility in this process is not yet known, despite that the importance of lateral organization and dynamics for LFA-1-mediated adhesion regulation is broadly recognized. Using single particle tracking approaches we here show that LFA-1 exhibits higher mobility on resting mDCs compared to monocytes. Lymphoid chemokine CCL21 stimulation of the LFA-1 high affinity state on mDCs, led to a significant reduction of mobility and an increase on the fraction of stationary receptors, consistent with re-activation of the receptor. Addition of soluble monomeric ICAM-1 in the presence of CCL21 did not alter the diffusion profile of LFA-1 while soluble ICAM-1 nano-aggregates in the presence of CCL21 further reduced LFA-1 mobility and readily bound to the receptor. Overall, our results emphasize the importance of LFA-1 lateral mobility across the membrane on the regulation of integrin activation and its function as adhesion receptor. Importantly, our data show that chemokines alone are not sufficient to trigger the high affinity state of the integrin based on the strict definition that affinity refers to the adhesion capacity of a single receptor to its ligand in solution. Instead our data indicate that nanoclustering of the receptor, induced by multi-ligand binding, is required to maintain stable cell adhesion once LFA-1 high affinity state is transiently triggered by inside-out signals.

  8. Beyond the mucus escalator: Complex ciliary hydrodynamics in disease and function

    Science.gov (United States)

    Nawroth, Janna; Guo, Hanliang; John, Dabiri; Kanso, Eva; McFall-Ngai, Margaret

    2015-11-01

    Cilia are microscopic, hair-like structures lining external and internal body surfaces where they interact with fluids. The main function of motile cilia is often described as that of a ``mucus escalator'', i.e., a homogeneous ciliary carpet moving along layer of mucus along the surface to transport food, germ cells, debris, or pathogens. Accordingly, the performance of ciliary systems is usually measured in terms of a single metric, transport velocity, or its presumed proxy, ciliary beat frequency. We challenge this simple view through the observation that both healthy and diseased biological systems exhibit a variety of cilia morphologies, beat patterns, and arrangements, resulting in complex flow patterns and transport phenomena that cannot be reduced to a single parameter. Here we present two case studies. In one system, the ciliated surface creates two distinct flow regimes for first trapping and then sheltering potential symbiont bacteria for further biochemical screening. In the other system, chronic disease induces a misalignment of ciliary beat, leading to a pathological transition from uniform mucus transport to a pattern of stagnation and circulation. These studies suggest that (a), we need to develop a wider range of metrics for describing ciliary transport in biological and clinical contexts, and (b), engineered ciliated systems exploiting a variety of design parameters could provide novel ways of manipulating fluids at the microscale.

  9. Platelet activation and aggregation

    DEFF Research Database (Denmark)

    Jensen, Maria Sander; Larsen, O H; Christiansen, Kirsten

    2013-01-01

    This study introduces a new laboratory model of whole blood platelet aggregation stimulated by endogenously generated thrombin, and explores this aspect in haemophilia A in which impaired thrombin generation is a major hallmark. The method was established to measure platelet aggregation initiated...

  10. Aggregations in Flatworms.

    Science.gov (United States)

    Liffen, C. L.; Hunter, M.

    1980-01-01

    Described is a school project to investigate aggregations in flatworms which may be influenced by light intensity, temperature, and some form of chemical stimulus released by already aggregating flatworms. Such investigations could be adopted to suit many educational levels of science laboratory activities. (DS)

  11. Experimental manipulation of sponge/bacterial symbiont community composition with antibiotics: sponge cell aggregates as a unique tool to study animal/microorganism symbiosis.

    Science.gov (United States)

    Richardson, Crystal; Hill, Malcolm; Marks, Carolyn; Runyen-Janecky, Laura; Hill, April

    2012-08-01

    Marine sponges can harbor dense and diverse bacterial communities, yet we have a limited understanding of important aspects of this symbiosis. We developed an experimental methodology that permits manipulating the composition of the microbial community. Specifically, we evaluated sponge cell aggregates (SCA) from Clathria prolifera that had been treated with different classes of antibiotics to determine whether this system might offer novel experimental approaches to the study of sponge/bacterial symbioses. Microscopic analysis of the SCA demonstrated that two distinct morphological types of microbiota existed on the external surface vs. the internal regions of the SCA. Denaturing gradient gel electrophoresis and sequence analysis of 16S rRNA gene clone libraries indicated that we were unable to create entirely aposymbiotic SCA but that different classes of antibiotics produced distinctive shifts in the SCA-associated bacterial community. After exposure to antibiotics, some bacterial species were 'revealed', thus uncovering novel components of the sponge-associated community. The antibiotic treatments used here had little discernible effect on the formation of SCA or subsequent development of the adult. The experimental approach we describe offers empirical options for studying the role symbionts play in sponge growth and development and for ascertaining relationships among bacterial species in communities residing in sponges.

  12. Aggregates from mineral wastes

    Directory of Open Access Journals (Sweden)

    Baic Ireneusz

    2016-01-01

    Full Text Available The problem concerning the growing demand for natural aggregates and the need to limit costs, including transportation from remote deposits, cause the increase in growth of interest in aggregates from mineral wastes as well as in technologies of their production and recovery. The paper presents the issue related to the group of aggregates other than natural. A common name is proposed for such material: “alternative aggregates”. The name seems to be fully justified due to adequacy of this term because of this raw materials origin and role, in comparison to the meaning of natural aggregates based on gravel and sand as well as crushed stones. The paper presents characteristics of the market and basic application of aggregates produced from mineral wastes, generated in the mining, power and metallurgical industries as well as material from demolished objects.

  13. Short-term Disulfiram to Reverse Latent HIV Infection: A Phase 2 Dose Escalation Study

    Science.gov (United States)

    Elliott, Julian H.; McMahon, James H.; Chang, Christina C.; Lee, Sulggi A.; Hartogensis, Wendy; Bumpus, Namandje; Savic, Rada; Roney, Janine; Hoh, Rebecca; Solomon, Ajantha; Piatak, Michael; Gorelick, Robert J.; Lifson, Jeff; Bacchetti, Peter; Deeks, Steven G.; Lewin, Sharon R.

    2016-01-01

    Background Disulfiram activates HIV transcription in a primary T-cell model of HIV latency and in a pilot clinical study increased plasma HIV RNA in individuals with adequate diulfiram exposure. Methods We conducted a prospective dose escalation study in order to optimise disulfiram exposure. Thirty people with HIV on suppressive antiretroviral therapy (ART) were enrolled, allocated sequentially to one of three dosing cohorts and received disulfiram daily for three days at a dose of 500mg, 1000mg or 2000mg. The primary endpoint was cell-associated unspliced (CA-US) HIV RNA in CD4+ T-cells. The study is registered with ClinicalTrials.gov, number NCT01944371. Findings The estimated fold increases in CA-US HIV RNA during and post-disulfiram for each cohort were: 500mg: 1·7 (95% confidence interval 1·3 – 2·2) and 2·1 (1·5 – 2·9); 1000mg: 1·9 (1·6 – 2·4) and 2·5 (1·9 – 3·3); and 2000mg: 1·6 (1·2 – 2·1) and 2·1 (1·5 – 3·1) respectively (p<0·003 for all). Disulfiram was well tolerated at all doses. Interpretation Short-term administration of disulfiram resulted in increases in CA-US HIV RNA at all doses, consistent with activating HIV latency. Disulfiram may be suited for future studies of combination and prolonged therapy to activate latent HIV. PMID:26614966

  14. Multilayer Dye Aggregation at Dye/TiO2 Interface via π…π Stacking and Hydrogen Bond and Its Impact on Solar Cell Performance: A DFT Analysis

    Science.gov (United States)

    Zhang, Lei; Liu, Xiaogang; Rao, Weifeng; Li, Jingfa

    2016-10-01

    Multilayer dye aggregation at the dye/TiO2 interface of dye-sensitized solar cells is probed via first principles calculations, using p-methyl red azo dye as an example. Our calculations suggest that the multilayer dye aggregates at the TiO2 surface can be stabilized by π…π stacking and hydrogen bond interactions. Compared with previous two-dimensional monolayer dye/TiO2 model, the multilayer dye aggregation model proposed in this study constructs a three-dimensional multilayer dye/TiO2 interfacial structure, and provides a better agreement between experimental and computational results in dye coverage and dye adsorption energy. In particular, a dimer forms by π…π stacking interactions between two neighboring azo molecules, while one of them chemisorbs on the TiO2 surface; a trimer may form by introducing one additional azo molecule on the dimer through a hydrogen bond between two carboxylic acid groups. Different forms of multilayer dye aggregates, either stabilized by π…π stacking or hydrogen bond, exhibit varied optical absorption spectra and electronic properties. Such variations could have a critical impact on the performance of dye sensitized solar cells.

  15. Artificial design of three-dimensional retina-like tissue from dissociated cells of the mammalian retina by rotation-mediated cell aggregation.

    Science.gov (United States)

    Rothermel, Andrée; Biedermann, Thomas; Weigel, Winnie; Kurz, Randy; Rüffer, Markus; Layer, Paul G; Robitzki, Andrea Anneliese

    2005-01-01

    The goal of this study was to establish a reliable three-dimensional culture system for the mammalian retina that allows the analysis of retinal function and dysfunction. To produce three-dimensional retinal tissues in vitro, dissociated retinal cells of neonatal rats were maintained in culture dishes on a self-made orbital shaker. On the basis of well-defined rotation conditions, dissociated free-floating cells reaggregate in the center of the culture dish to form a multicellular cluster. Subsequently, cells begin to proliferate, whereby they form spherelike retinal tissues that grow to a size of 180-210 microm. Immunohistochemical characterization of mature retinal spheres revealed the presence of ganglion cells, amacrine cells, Müller cells, and rod photoreceptors, which are arranged in different retina-like layers. Although a small number of cells undergo programmed cell death, retinal spheres remain viable for at least 35 days in culture as revealed by fluorescein diacetate and TUNEL staining. Because most biological processes involved in tissue organization such as proliferation, differentiation, apoptosis, and survival are also observable in retinal spheres, the presented novel mammalian three-dimensional culture system is not only an outstanding model for basic research but may also be of great benefit for stem cell tissue engineering and the pharmaceutical industry.

  16. Protein aggregate myopathies

    Directory of Open Access Journals (Sweden)

    Sharma M

    2005-01-01

    Full Text Available Protein aggregate myopathies (PAM are an emerging group of muscle diseases characterized by structural abnormalities. Protein aggregate myopathies are marked by the aggregation of intrinsic proteins within muscle fibers and fall into four major groups or conditions: (1 desmin-related myopathies (DRM that include desminopathies, a-B crystallinopathies, selenoproteinopathies caused by mutations in the, a-B crystallin and selenoprotein N1 genes, (2 hereditary inclusion body myopathies, several of which have been linked to different chromosomal gene loci, but with as yet unidentified protein product, (3 actinopathies marked by mutations in the sarcomeric ACTA1 gene, and (4 myosinopathy marked by a mutation in the MYH-7 gene. While PAM forms 1 and 2 are probably based on impaired extralysosomal protein degradation, resulting in the accumulation of numerous and diverse proteins (in familial types in addition to respective mutant proteins, PAM forms 3 and 4 may represent anabolic or developmental defects because of preservation of sarcomeres outside of the actin and myosin aggregates and dearth or absence of other proteins in these actin or myosin aggregates, respectively. The pathogenetic principles governing protein aggregation within muscle fibers and subsequent structural sarcomeres are still largely unknown in both the putative catabolic and anabolic forms of PAM. Presence of inclusions and their protein composition in other congenital myopathies such as reducing bodies, cylindrical spirals, tubular aggregates and others await clarification. The hitherto described PAMs were first identified by immunohistochemistry of proteins and subsequently by molecular analysis of their genes.

  17. Charged Dust Aggregate Interactions

    Science.gov (United States)

    Matthews, Lorin; Hyde, Truell

    2015-11-01

    A proper understanding of the behavior of dust particle aggregates immersed in a complex plasma first requires a knowledge of the basic properties of the system. Among the most important of these are the net electrostatic charge and higher multipole moments on the dust aggregate as well as the manner in which the aggregate interacts with the local electrostatic fields. The formation of elongated, fractal-like aggregates levitating in the sheath electric field of a weakly ionized RF generated plasma discharge has recently been observed experimentally. The resulting data has shown that as aggregates approach one another, they can both accelerate and rotate. At equilibrium, aggregates are observed to levitate with regular spacing, rotating about their long axis aligned parallel to the sheath electric field. Since gas drag tends to slow any such rotation, energy must be constantly fed into the system in order to sustain it. A numerical model designed to analyze this motion provides both the electrostatic charge and higher multipole moments of the aggregate while including the forces due to thermophoresis, neutral gas drag, and the ion wakefield. This model will be used to investigate the ambient conditions leading to the observed interactions. This research is funded by NSF Grant 1414523.

  18. Aggregated Computational Toxicology Online Resource

    Data.gov (United States)

    U.S. Environmental Protection Agency — Aggregated Computational Toxicology Online Resource (AcTOR) is EPA's online aggregator of all the public sources of chemical toxicity data. ACToR aggregates data...

  19. Terrorist attacks escalate in frequency and fatalities preceding highly lethal attacks.

    Science.gov (United States)

    Martens, Andy; Sainudiin, Raazesh; Sibley, Chris G; Schimel, Jeff; Webber, David

    2014-01-01

    Highly lethal terrorist attacks, which we define as those killing 21 or more people, account for 50% of the total number of people killed in all terrorist attacks combined, yet comprise only 3.5% of terrorist attacks. Given the disproportionate influence of these incidents, uncovering systematic patterns in attacks that precede and anticipate these highly lethal attacks may be of value for understanding attacks that exact a heavy toll on life. Here we examined whether the activity of terrorist groups escalates--both in the number of people killed per attack and in the frequency of attacks--leading up to highly lethal attacks. Analyses of terrorist attacks drawn from a state-of-the-art international terrorism database (The Global Terrorism Database) showed evidence for both types of escalation leading up to highly lethal attacks, though complexities to the patterns emerged as well. These patterns of escalation do not emerge among terrorist groups that never commit a highly lethal attack.

  20. Promoting de-escalation of commitment: a regulatory-focus perspective on sunk costs.

    Science.gov (United States)

    Molden, Daniel C; Hui, Chin Ming

    2011-01-01

    People frequently escalate their commitment to failing endeavors. Explanations for such behavior typically involve loss aversion, failure to recognize other alternatives, and concerns with justifying prior actions; all of these factors produce recommitment to previous decisions with the goal of erasing losses and vindicating these decisions. Solutions to escalation of commitment have therefore focused on external oversight and divided responsibility during decision making to attenuate loss aversion, blindness to alternatives, and justification biases. However, these solutions require substantial resources and have additional adverse effects. The present studies tested an alternative method for de-escalating commitment: activating broad motivations for growth and advancement (promotion). This approach should reduce concerns with loss and increase perceptions of alternatives, thereby attenuating justification motives. In two studies featuring hypothetical financial decisions, activating promotion motivations reduced recommitment to poorly performing investments as compared with both not activating any additional motivations and activating motivations for safety and security (prevention).

  1. Audience reactions to peace journalism: How supporters and critics of the Israeli policy process escalation and de-escalation oriented media frames

    Directory of Open Access Journals (Sweden)

    Stephanie Thiel

    2014-04-01

    Full Text Available This paper reports on an experiment that uses the Israeli-Palestinian conflict as a natural laboratory for studying how recipients make sense of escalation vs. de-escalation oriented news articles. The results of the study indicate that media frames and individual frames have both a direct effect and complex interaction effects on participants’ text understanding. Particularly the effect of media war frames diminishes if they are incongruent with participants’ individual frames, and the propaganda function of reports about violence and human casualties can be neutralized if framed according to a peace frame. If participants had a priori positioned themselves in favor of the perpetrator, they may produce reactance, however.

  2. Recycled aggregates concrete: aggregate and mix properties

    Directory of Open Access Journals (Sweden)

    González-Fonteboa, B.

    2005-09-01

    Full Text Available This study of structural concrete made with recycled concrete aggregate focuses on two issues: 1. The characterization of such aggregate on the Spanish market. This involved conducting standard tests to determine density, water absorption, grading, shape, flakiness and hardness. The results obtained show that, despite the considerable differences with respect to density and water absorption between these and natural aggregates, on the whole recycled aggregate is apt for use in concrete production. 2. Testing to determine the values of basic concrete properties: mix design parameters were established for structural concrete in non-aggressive environments. These parameters were used to produce conventional concrete, and then adjusted to manufacture recycled concrete aggregate (RCA concrete, in which 50% of the coarse aggregate was replaced by the recycled material. Tests were conducted to determine the physical (density of the fresh and hardened material, water absorption and mechanical (compressive strength, splitting tensile strength and modulus of elasticity properties. The results showed that, from the standpoint of its physical and mechanical properties, concrete in which RCA accounted for 50% of the coarse aggregate compared favourably to conventional concrete.

    Se aborda el estudio de hormigones estructurales fabricados con áridos reciclados procedentes de hormigón, incidiéndose en dos aspectos: 1. Caracterización de tales áridos, procedentes del mercado español. Para ello se llevan a cabo ensayos de densidad, absorción, granulometría, coeficiente de forma, índice de lajas y dureza. Los resultados obtenidos han puesto de manifiesto que, a pesar de que existen diferencias notables (sobre todo en cuanto a densidad y absorción con los áridos naturales, las características de los áridos hacen posible la fabricación de hormigones. 2. Ensayos sobre propiedades básicas de los hormigones: se establecen parámetros de dosificaci

  3. Choosing between stairs and escalators in China: The impact of location, height and pedestrian volume

    Science.gov (United States)

    Zacharias, John; Tang, Boshen

    2015-01-01

    Objective This research examines whether Beijing residents are more or less likely than Montréal residents to avoid stair climbing, by replicating a study in Montréal, Canada that measured the impacts of distance between stairs and escalator, height between floors and pedestrian volume on stair climbing rate. Method 15 stairways, 14 up-escalators and 13 down-escalators were selected in 13 publicly accessible settings in Beijing. Distance between the bottom or top of nearest stair and escalator combinations varied from 2.1 m to 114.1 m with height between floors varying from 3.3 m to 21.7 m. Simultaneous counts were conducted on stair and escalator pairs, for a total of 37,081 counted individuals. Results In the ascent model, pedestrian volume accounted for 16.3% of variance in stair climbing, 16.4% when height was added and 45.1% when distance was added. In the descent model, 40.9% of variance was explained by pedestrian volume, 41.5% when height was added and 45.5% when distance was added. Conclusion Separating stairs and escalator is effective in increasing stair climbing in Beijing, accounting for 29% of the variance in stair climbing, compared with 43% in Montreal. As in the Montreal case, distance has less effect on stair use rate when descending. Overall, 25.4% of Beijingers opted for stairs when ascending compared with 20.3% of Montrealers, and for descending 32.8% and 31.1% respectively. PMID:26844113

  4. Aggregation and Averaging.

    Science.gov (United States)

    Siegel, Irving H.

    The arithmetic processes of aggregation and averaging are basic to quantitative investigations of employment, unemployment, and related concepts. In explaining these concepts, this report stresses need for accuracy and consistency in measurements, and describes tools for analyzing alternative measures. (BH)

  5. Protein Colloidal Aggregation Project

    Science.gov (United States)

    Oliva-Buisson, Yvette J. (Compiler)

    2014-01-01

    To investigate the pathways and kinetics of protein aggregation to allow accurate predictive modeling of the process and evaluation of potential inhibitors to prevalent diseases including cataract formation, chronic traumatic encephalopathy, Alzheimer's Disease, Parkinson's Disease and others.

  6. Verbal De-escalation of the Agitated Patient: Consensus Statement of the American Association for Emergency Psychiatry Project BETA De-escalation Workgroup

    Directory of Open Access Journals (Sweden)

    Janet S. Richmond

    2012-04-01

    Full Text Available Agitation is an acute behavioral emergency requiring immediate intervention. Traditional methods of treating agitated patients, ie, routine restraints and involuntary medication, have been replaced with a much greater emphasis on a noncoercive approach. Experienced practitioners have found that if such interventions are undertaken with genuine commitment, successful outcomes can occur far more often than previously thought possible. In the new paradigm, a 3-step approach is used. First, the patient is verbally engaged; then a collaborative relationship is established; and, finally, the patient is verbally deescalated out of the agitated state. Verbal de-escalation is usually the key to engaging the patient and helping him become an active partner in his evaluation and treatment; although, we also recognize that in some cases nonverbal approaches, such as voluntary medication and environment planning, are also important. When working with an agitated patient, there are 4 main objectives: (1 ensure the safety of the patient, staff, and others in the area; (2 help the patient manage his emotions and distress and maintain or regain control of his behavior; (3 avoid the use of restraint when at all possible; and (4 avoid coercive interventions that escalate agitation. The authors detail the proper foundations for appropriate training for de-escalation and provide intervention guidelines, using the ‘‘10 domains of deescalation.’’ [West J Emerg Med. 2012;13(1:17–25.

  7. Safety and immunogenicity of the PRAME cancer immunotherapeutic in metastatic melanoma: results of a phase I dose escalation study

    Science.gov (United States)

    Gutzmer, R; Rivoltini, L; Levchenko, E; Testori, A; Utikal, J; Ascierto, P A; Demidov, L; Grob, J J; Ridolfi, R; Schadendorf, D; Queirolo, P; Santoro, A; Loquai, C; Dreno, B; Hauschild, A; Schultz, E; Lesimple, T P; Vanhoutte, N; Salaun, B; Gillet, M; Jarnjak, S; De Sousa Alves, P M; Louahed, J; Brichard, V G; Lehmann, F F

    2016-01-01

    Purpose The PRAME tumour antigen is expressed in several tumour types but in few normal adult tissues. A dose-escalation phase I/II study (NCT01149343) assessed the safety, immunogenicity and clinical activity of the PRAME immunotherapeutic (recombinant PRAME protein (recPRAME) with the AS15 immunostimulant) in patients with advanced melanoma. Here, we report the phase I dose-escalation study segment. Patients and methods Patients with stage IV PRAME-positive melanoma were enrolled to 3 consecutive cohorts to receive up to 24 intramuscular injections of the PRAME immunotherapeutic. The RecPRAME dose was 20, 100 or 500 µg in cohorts 1, 2 and 3, respectively, with a fixed dose of AS15. Adverse events (AEs), including predefined dose-limiting toxicity (DLT) and the anti-PRAME humoral response (ELISA), were coprimary end points. Cellular immune responses were evaluated using in vitro assays. Results 66 patients were treated (20, 24 and 22 in the respective cohorts). AEs considered by the investigator to be causally related were mostly grade 1 or 2 injection site symptoms, fatigue, chills, fever and headache. Two DLTs (grade 3 brain oedema and proteinuria) were recorded in two patients in two cohorts (cohorts 2 and 3). All patients had detectable anti-PRAME antibodies after four immunisations. Percentages of patients with predefined PRAME-specific-CD4+T-cell responses after four immunisations were similar in each cohort. No CD8+ T-cell responses were detected. Conclusions The PRAME immunotherapeutic had an acceptable safety profile and induced similar anti-PRAME-specific humoral and cellular immune responses in all cohorts. As per protocol, the phase II study segment was initiated to further evaluate the 500 µg PRAME immunotherapeutic dose. Trial registration number NCT01149343, Results. PMID:27843625

  8. De-escalation empirical antibiotic therapy improved survival for patients with severe aplastic anemia treated with antithymocyte globulin.

    Science.gov (United States)

    Fu, Rong; Chen, Tong; Song, Jia; Wang, Guojin; Li, Lijuan; Ruan, Erbao; Liu, Hui; Wang, Yihao; Wang, Huaquan; Xing, Limin; Wu, Yuhong; Liu, Hong; Qu, Wen; Shao, Zonghong

    2017-02-01

    We aimed to investigate the efficacy and safety of de-escalation empirical therapy for controlling infection in patients with severe aplastic anaemia (SAA) treated with antithymocyte globulin (ATG). Eighty-seven ATG-treated SAA patients who had microbiological culture-confirmed infections from 2006 to 2015 in our center were retrospectively analyzed. The efficacy of de-escalation and non-de-escalation therapy was compared. Among all 87 patients, 63 patients were treated with de-escalation therapy and 24 patients with non-de-escalation therapy. More patients showed response to anti-infection treatment in de-escalation group than in non-de-escalation group both on day 7 (60.32% vs. 25.00%, P = 0.003) and on day 30 (79.37% vs. 58.33%, P = 0.047) since the initial antimicrobial therapy. On day 30, more patients had increased absolute neutrophil count in de-escalation group compared with non-de-escalation group (76.19% vs. 45.83%, P = 0.007), and de-escalation group had lower morality rate (17.46% vs. 37.50%, P = 0.047) and better survival outcome (P = 0.023) on day 90. Twenty-three patients in de-escalation group and 5 patients in non-escalation group received granulocyte transfusions. Granulocyte transfusions helped to control infections in both de-escalation group (P = 0.027) and non-de-escalation group (P = 0.042) on day 7, but did not improve survival on day 90. We concluded that de-escalation antibiotics improved survival in SAA patients after ATG treatment. Early administration of broad-spectrum antibiotics pending microbiological cultures combined with a commitment to change to narrow-spectrum antibiotics should be recommended for controlling infections in SAA patients treated with ATG. Granulocyte transfusions might be an adjunctive therapy in controlling infections.

  9. Inhomogeneous dose escalation increases expected local control for NSCLC patients with lymph node involvement without increased mean lung dose

    DEFF Research Database (Denmark)

    Nielsen, Tine B; Hansen, Olfred; Schytte, Tine;

    2014-01-01

    in mediastinum, and the thorax wall. The dose was escalated using a TCP model implemented into the planning system. The difference in TCP values between the homogeneous and inhomogeneous plans were evaluated using two different TCP models. RESULTS: Dose escalation was possible for all patients. TCP values based...

  10. Optical dynamics of molecular aggregates

    NARCIS (Netherlands)

    de Boer, Steven

    2006-01-01

    The subject of this thesis is the spectroscopy and dynamics of molecular aggregates in amorphous matrices. Aggregates of three different molecules were studied. The molecules are depicted in Fig. (1.1). Supersaturated solutions of these molecules show aggregate formation. Aggregation is a process si

  11. North Korea’s Provocation and Escalation Calculus: Dealing with the Kim Jong-un Regime

    Science.gov (United States)

    2015-08-01

    level” provocations while minimizing risks of potential rapid conflict escalation remains a central dilemma as was demonstrated in the reaction to North...Korean summit because of Seoul’s attempts to “depolitize” the event by keeping it purely at “the artistic, athletic, and cultural ” level. This was

  12. Some Take the Glass Escalator, Some Hit the Glass Ceiling? Career Consequences of Occupational Sex Segregation.

    Science.gov (United States)

    Hultin, Mia

    2003-01-01

    Analysis of Swedish longitudinal data (1,535 men, 1,584 women) showed that men in female-dominated occupations have substantially better internal promotion opportunities than equally qualified women. In male-dominated occupations, men and women have equal internal promotion chances. Results suggest a "glass escalator" advantage for men…

  13. Siding and other reactions to a conflict: A theory of escalation toward outsiders

    NARCIS (Netherlands)

    Van de Vliert, E

    1981-01-01

    Siding in a dyadic conflict is important because it precipitates escalation. Nevertheless, little is known about how and why a nonprofessional outsider (P) reacts when a conflict party puts him under pressure to take sides. Coalition and role conflict theories suggest four behavior alternatives (tak

  14. A Dynamical Tool to Study the Cultural Context of Conflict Escalation

    Science.gov (United States)

    2009-07-13

    advancing here is aimedt,. at identifying naturally occurrin se uences in escala . n d ’. . ,., time controlling for cultural conditions which couJd...escalation of provocation by a colleague at work, & om a relatively mild disagreement ("Your colleague criticizes your work") to open confrontation and

  15. The Effect of Image Compatibility and Escalation of Commitment on Decision Performance

    Directory of Open Access Journals (Sweden)

    Harris K. Turino

    2012-04-01

    Full Text Available This study aims at empirically examining the extent to which Image Theory, initially developed as a theoretical basis for selecting a strategy or a decision, can be a theoretical basis for predicting a decision performance in two opposite frames: positive and negative. Image compatibility are employed to operationalize such a theory and the decision under study is progress decision represented by escalation of commitment. Thus, this study also empirically examines the connection between image compatibility and escalation of commitment as well as escalation of commitment as a mediator of the relationship between image compatibility and decision performance. The research context is Indonesia Stock Exchange (IDX that suffered from crisis in the past year (negative frame yet has been recovered recently (positive frame. The respondents are 229 individual investors in IDX. They are involved in day-to-day decision making (progress decision making with regard to their investment portofolio. The results of this study show that high image compatibility tends to lead to better decision performance in both frames. However, image compatibility may only positively affect the escalation of commitment in positive frame

  16. Deterrence Without Escalation:A Case for the Arctic in 2040

    Science.gov (United States)

    2015-04-08

    and dangerous weather conditions, which make traditional power projection methods less effective. Furthermore, the distances in the Arctic are vast...AIR COMMAND AND STAFF COLLEGE AIR UNIVERSITY Deterrence Without Escalation: A Case for the Arctic in 2040 by Erik Carlson, Maj...1 2. The Arctic in 2040

  17. Temporal Aspects of Moral Disengagement in School Bullying: Crystallization or Escalation?

    Science.gov (United States)

    Obermann, Marie-Louise

    2013-01-01

    This study investigated the stability and change in bullying behavior and their relation to increases and decreases in moral disengagement, specifically exploring whether crystallization and escalation of disengagement occur. Within a 1-year span, two sets of data were collected. A total of 567 sixth to eighth graders participated in both data…

  18. 18 CFR Table 1 to Part 301 - Functionalization and Escalation Codes

    Science.gov (United States)

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Functionalization and Escalation Codes 1 Table 1 to Part 301 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS FOR FEDERAL POWER MARKETING ADMINISTRATIONS AVERAGE SYSTEM...

  19. Unique cellular events occurring during the initial interaction of macrophages with matrix-retained or methylated aggregated low density lipoprotein (LDL). Prolonged cell-surface contact during which ldl-cholesteryl ester hydrolysis exceeds ldl protein degradation.

    Science.gov (United States)

    Buton, X; Mamdouh, Z; Ghosh, R; Du, H; Kuriakose, G; Beatini, N; Grabowski, G A; Maxfield, F R; Tabas, I

    1999-11-05

    A critical event in atherogenesis is the interaction of arterial wall macrophages with subendothelial lipoproteins. Although most studies have investigated this interaction by incubating cultured macrophages with monomeric lipoproteins dissolved in media, arterial wall macrophages encounter lipoproteins that are mostly bound to subendothelial extracellular matrix, and these lipoproteins are often aggregated or fused. Herein, we utilize a specialized cell-culture system to study the initial interaction of macrophages with aggregated low density lipoprotein (LDL) bound to extracellular matrix. The aggregated LDL remains extracellular for a relatively prolonged period of time and becomes lodged in invaginations in the surface of the macrophages. As expected, the degradation of the protein moiety of the LDL was very slow. Remarkably, however, hydrolysis of the cholesteryl ester (CE) moiety of the LDL was 3-7-fold higher than that of the protein moiety, in stark contrast to the situation with receptor-mediated endocytosis of acetyl-LDL. Similar results were obtained using another experimental system in which the degradation of aggregated LDL protein was delayed by LDL methylation rather than by retention on matrix. Additional experiments indicated the following properties of this interaction: (a) LDL-CE hydrolysis is catalyzed by lysosomal acid lipase; (b) neither scavenger receptors nor the LDL receptor appear necessary for the excess LDL-CE hydrolysis; and (c) LDL-CE hydrolysis in this system is resistant to cellular potassium depletion, which further distinguishes this process from receptor-mediated endocytosis. In summary, experimental systems specifically designed to mimic the in vivo interaction of arterial wall macrophages with subendothelial lipoproteins have demonstrated an initial period of prolonged cell-surface contact in which CE hydrolysis exceeds protein degradation.

  20. Fractals of Silica Aggregates

    Institute of Scientific and Technical Information of China (English)

    ZhinhongLi; DongWu; Yuhansun; JunWang; YiLiu; BaozhongDong; Zhinhong

    2001-01-01

    Silica aggregates were prepared by base-catalyzed hydrolysis and condensation of alkoxides in alcohol.Polyethylene glycol(PEG) was used as organic modifier.The sols were characterized using Small Angle X-ray Scattering (SAXS) with synchrotron radiation as X-ray source.The structure evolution during the sol-gel process was determined and described in terms of the fractal geometry.As-produced silica aggregates were found to be mass fractals.The fractl dimensions spanned the regime 2.1-2.6 corresponding to more branched and compact structures.Both RLCA and Eden models dominated the kinetic growth under base-catalyzed condition.

  1. Cholesterol impairment contributes to neuroserpin aggregation

    Science.gov (United States)

    Giampietro, Costanza; Lionetti, Maria Chiara; Costantini, Giulio; Mutti, Federico; Zapperi, Stefano; La Porta, Caterina A. M.

    2017-03-01

    Intraneural accumulation of misfolded proteins is a common feature of several neurodegenerative pathologies including Alzheimer’s and Parkinson’s diseases, and Familial Encephalopathy with Neuroserpin Inclusion Bodies (FENIB). FENIB is a rare disease due to a point mutation in neuroserpin which accelerates protein aggregation in the endoplasmic reticulum (ER). Here we show that cholesterol depletion induced either by prolonged exposure to statins or by inhibiting the sterol reg-ulatory binding-element protein (SREBP) pathway also enhances aggregation of neuroserpin proteins. These findings can be explained considering a computational model of protein aggregation under non-equilibrium conditions, where a decrease in the rate of protein clearance improves aggregation. Decreasing cholesterol in cell membranes affects their biophysical properties, including their ability to form the vesicles needed for protein clearance, as we illustrate by a simple mathematical model. Taken together, these results suggest that cholesterol reduction induces neuroserpin aggregation, even in absence of specific neuroserpin mutations. The new mechanism we uncover could be relevant also for other neurodegenerative diseases associated with protein aggregation.

  2. Cholesterol impairment contributes to neuroserpin aggregation

    Science.gov (United States)

    Giampietro, Costanza; Lionetti, Maria Chiara; Costantini, Giulio; Mutti, Federico; Zapperi, Stefano; La Porta, Caterina A. M.

    2017-01-01

    Intraneural accumulation of misfolded proteins is a common feature of several neurodegenerative pathologies including Alzheimer’s and Parkinson’s diseases, and Familial Encephalopathy with Neuroserpin Inclusion Bodies (FENIB). FENIB is a rare disease due to a point mutation in neuroserpin which accelerates protein aggregation in the endoplasmic reticulum (ER). Here we show that cholesterol depletion induced either by prolonged exposure to statins or by inhibiting the sterol reg-ulatory binding-element protein (SREBP) pathway also enhances aggregation of neuroserpin proteins. These findings can be explained considering a computational model of protein aggregation under non-equilibrium conditions, where a decrease in the rate of protein clearance improves aggregation. Decreasing cholesterol in cell membranes affects their biophysical properties, including their ability to form the vesicles needed for protein clearance, as we illustrate by a simple mathematical model. Taken together, these results suggest that cholesterol reduction induces neuroserpin aggregation, even in absence of specific neuroserpin mutations. The new mechanism we uncover could be relevant also for other neurodegenerative diseases associated with protein aggregation. PMID:28255164

  3. Growth hormone aggregates in the rat adenohypophysis

    Science.gov (United States)

    Farrington, M.; Hymer, W. C.

    1990-01-01

    Although it has been known for some time that GH aggregates are contained within the rat anterior pituitary gland, the role that they might play in pituitary function is unknown. The present study examines this issue using the technique of Western blotting, which permitted visualization of 11 GH variants with apparent mol wt ranging from 14-88K. Electroelution of the higher mol wt variants from gels followed by their chemical reduction with beta-mercaptoethanol increased GH immunoassayability by about 5-fold. With the blot procedure we found 1) that GH aggregates greater than 44K were associated with a 40,000 x g sedimentable fraction; 2) that GH aggregates were not present in glands from thyroidectomized rats, but were in glands from the thyroidectomized rats injected with T4; 3) that GH aggregates were uniquely associated with a heavily granulated somatotroph subpopulation isolated by density gradient centrifugation; and 4) that high mol wt GH forms were released from the dense somatotrophs in culture, since treatment of the culture medium with beta-mercaptoethanol increased GH immunoassayability by about 5-fold. Taken together, the results show that high mol wt GH aggregates are contained in secretory granules of certain somatotrophs and are also released in aggregate form from these cells in vitro.

  4. Detection of ubiquitinated huntingtin species in intracellular aggregates

    Directory of Open Access Journals (Sweden)

    Katrin eJuenemann

    2015-01-01

    Full Text Available Protein conformation diseases, including polyglutamine diseases, result from the accumulation and aggregation of misfolded proteins. Huntington’s disease is one of nine diseases caused by an expanded polyglutamine repeat within the affected protein and is hallmarked by intracellular inclusion bodies composed of aggregated N-terminal huntingtin fragments and other sequestered proteins. Fluorescence microscopy and filter trap assay are conventional methods to study protein aggregates, but cannot be used to analyze the presence and levels of post-translational modifications of aggregated huntingtin such as ubiquitination. Ubiquitination of proteins can be a signal for degradation and intracellular localization, but also affects protein activity and protein-protein interactions. The function of ubiquitination relies on its mono- and polymeric isoforms attached to protein substrates. Studying the ubiquitination pattern of aggregated huntingtin fragments offers an important possibility to understand huntingtin degradation and aggregation processes within the cell. For the identification of aggregated huntingtin and its ubiquitinated species, solubilization of the cellular aggregates is mandatory. Here we describe methods to identify post-translational modifications such as ubiquitination of aggregated mutant huntingtin. This approach is specifically described for use with mammalian cell culture and is suitable to study other disease-related proteins prone to aggregate.

  5. Erosion of dust aggregates

    CERN Document Server

    Seizinger, Alexander; Kley, Wilhelm

    2013-01-01

    Aims: The aim of this work is to gain a deeper insight into how much different aggregate types are affected by erosion. Especially, it is important to study the influence of the velocity of the impacting projectiles. We also want to provide models for dust growth in protoplanetary disks with simple recipes to account for erosion effects. Methods: To study the erosion of dust aggregates we employed a molecular dynamics approach that features a detailed micro-physical model of the interaction of spherical grains. For the first time, the model has been extended by introducing a new visco-elastic damping force which requires a proper calibration. Afterwards, different sample generation methods were used to cover a wide range of aggregate types. Results: The visco-elastic damping force introduced in this work turns out to be crucial to reproduce results obtained from laboratory experiments. After proper calibration, we find that erosion occurs for impact velocities of 5 m/s and above. Though fractal aggregates as ...

  6. Diffusion in aggregated soil.

    NARCIS (Netherlands)

    Rappoldt, C.

    1992-01-01

    The structure of an aggregated soil is characterized by the distribution of the distance from an arbitrary point in the soil to the nearest macropore or crack. From this distribution an equivalent model system is derived to which a diffusion model can be more easily applied. The model system consist

  7. Two experiments focusing on de-escalation oriented coverage of post-war conflicts

    Directory of Open Access Journals (Sweden)

    Wilhelm Kempf

    2005-10-01

    Full Text Available War coverage has a strong bias towards the promotion of conflict escalation and - though less pronounced - this bias often survives in post-war coverage as well. Even after the end of war, only a minority of journalists frame conflict in a firmly de-escalation oriented way. Do they have a chance to reach the public? Will their reports be respected by the audience as more balanced and unbiased? Will they have an impact on the audience's mental models of the conflict? Or will the audience continue to cling to its prejudices and reject news articles which do not affirm the enemy images that emerged during wartime? The present paper investigates these questions by means of two experimental studies. In the first experiment, news articles on three events in former Yugoslavia after the fall of Milosevic were presented to a total of n = 128 subjects, representative of the readership of the German quality press: (1 violent conflicts in Southern Serbia (December 2000, (2 the extradition of Milosevic to The Hague (June, 2001 and (3 the treaty between Serbia and Montenegro (March 2003. For each of the events, four different types of articles were used: moderately escalation oriented articles from prestigious German newspapers (Die Welt, Frankfurter Allgemeine Zeitung, Süddeutsche Zeitung and three variants of these articles, (a with increased escalation-oriented framing, (b with moderate de-escalation oriented framing and (c with more strongly de-escalation oriented framing of the events. Each subject was asked to read one article on each of the three events in chronological order and after each article (a to narrate the reported events in their own words and (b to fill out a questionnaire designed to measure the acceptance of the articles as unbiased, well-balanced, interesting, etc. The subjects' mental models of the reported events were inferred from their narratives by means of quantitative content analysis. The second experiment measured the

  8. Dose escalation in permanent brachytherapy for prostate cancer: dosimetric and biological considerations

    Energy Technology Data Exchange (ETDEWEB)

    Li, X Allen [Department of Radiation Oncology, University of Maryland, School of Medicine, 22 South Greene Street, Baltimore, MD 21201-1595 (United States); Wang, Jian Z [Department of Radiation Oncology, University of Maryland, School of Medicine, 22 South Greene Street, Baltimore, MD 21201-1595 (United States); Stewart, Robert D [School of Health Sciences, Purdue University, West Lafayette, IN 47907-1338 (United States); Di Biase, Steven J [Department of Radiation Oncology, University of Maryland, School of Medicine, 22 South Greene Street, Baltimore, MD 21201-1595 (United States)

    2003-09-07

    No prospective dose escalation study for prostate brachytherapy (PB) with permanent implants has been reported. In this work, we have performed a dosimetric and biological analysis to explore the implications of dose escalation in PB using {sup 125}I and {sup 103}Pd implants. The concept of equivalent uniform dose (EUD), proposed originally for external-beam radiotherapy (EBRT), is applied to low dose rate brachytherapy. For a given {sup 125}I or {sup 103}Pd PB, the EUD for tumour that corresponds to a dose distribution delivered by EBRT is calculated based on the linear quadratic model. The EUD calculation is based on the dose volume histogram (DVH) obtained retrospectively from representative actual patient data. Tumour control probabilities (TCPs) are also determined in order to compare the relative effectiveness of different dose levels. The EUD for normal tissue is computed using the Lyman model. A commercial inverse treatment planning algorithm is used to investigate the feasibility of escalating the dose to prostate with acceptable dose increases in the rectum and urethra. The dosimetric calculation is performed for five representative patients with different prostate sizes. A series of PB dose levels are considered for each patient using {sup 125}I and {sup 103}Pd seeds. It is found that the PB prescribed doses (minimum peripheral dose) that give an equivalent EBRT dose of 64.8, 70.2, 75.6 and 81 Gy with a fraction size of 1.8 Gy are 129, 139, 150 and 161 Gy for {sup 125}I and 103, 112, 122 and 132 Gy for {sup 103}Pd implants, respectively. Estimates of the EUD and TCP for a series of possible prescribed dose levels (e.g., 145, 160, 170 and 180 Gy for {sup 125}I and 125, 135, 145 and 155 for {sup 103}Pd implants) are tabulated. The EUD calculation was found to depend strongly on DVHs and radiobiological parameters. The dosimetric calculations suggest that the dose to prostate can be escalated without a substantial increase in both rectal and urethral dose

  9. Synphilin-1 enhances α-synuclein aggregation in yeast and contributes to cellular stress and cell death in a Sir2-dependent manner.

    OpenAIRE

    Sabrina Büttner; Charlotte Delay; Vanessa Franssens; Tine Bammens; Doris Ruli; Sandra Zaunschirm; Rita Machado de Oliveira; Tiago Fleming Outeiro; Frank Madeo; Luc Buée; Marie-Christine Galas; Joris Winderickx

    2010-01-01

    © 2010 Büttner et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Background: Parkinson’s disease is characterized by the presence of cytoplasmic inclusions, known as Lewy bodies, containing both aggregated α-synuclein and its interaction partner, synphilin-1. While synphilin-1 is known to accelerate ...

  10. Antipsychotic dose escalation as a trigger for Neuroleptic Malignant Syndrome (NMS: literature review and case series report

    Directory of Open Access Journals (Sweden)

    Langan Julie

    2012-11-01

    Full Text Available Abstract Background “Neuroleptic malignant syndrome” (NMS is a potentially fatal idiosyncratic reaction to any medication which affects the central dopaminergic system. Between 0.5% and 1% of patients exposed to antipsychotics develop the condition. Mortality rates may be as high as 55% and many risk factors have been reported. Although rapid escalation of antipsychotic dose is thought to be an important risk factor, to date it has not been the focus of a published case series or scientifically defined. Description We aimed to identify cases of NMS and review risk factors for its development with a particular focus on rapid dose escalation in the 30 days prior to onset. A review of the literature on rapid dose escalation was undertaken and a pragmatic definition of “rapid dose escalation” was made. NMS cases were defined using DSM-IV criteria and systematically identified within a secondary care mental health service. A ratio of titration rate was calculated for each NMS patient and “rapid escalators” and “non rapid escalators” were compared. 13 cases of NMS were identified. A progressive mean dose increase 15 days prior to the confirmed episode of NMS was observed (241.7 mg/day during days 1–15 to 346.9 mg/day during days 16–30 and the mean ratio of dose escalation for NMS patients was 1.4. Rapid dose escalation was seen in 5/13 cases and non rapid escalators had markedly higher daily cumulative antipsychotic dose compared to rapid escalators. Conclusions Rapid dose escalation occurred in less than half of this case series (n = 5, 38.5%, although there is currently no consensus on the precise definition of rapid dose escalation. Cumulative antipsychotic dose – alongside other known risk factors - may also be important in the development of NMS.

  11. Coping with Violence in Mental Health Care Settings: Patient and Staff Member Perspectives on De-escalation Practices.

    Science.gov (United States)

    Berring, Lene Lauge; Pedersen, Liselotte; Buus, Niels

    2016-10-01

    This multiple case study explored de-escalation processes in threatening and violent situations based on patients and staff members perspectives. Our post hoc analysis indicated that de-escalation included responsive interactions influenced by the perspectives of both patients and staff members. We assembled their perspectives in a mental model consisting of three interdependent stages: (1) memories and hope, (2) safety and creativity and (3) reflective moments. The data indicated that both patients and staff strived for peaceful solutions and that a dynamic and sociological understanding of de-escalation can foster shared problem solving in violent and threatening situations.

  12. Developmental competence of porcine chimeric embryos produced by aggregation

    DEFF Research Database (Denmark)

    Li, Juan; Jakobsen, Jannik E.; Xiong, Qiang

    2015-01-01

    The purpose of our study was to compare the developmental competence and blastomere allocation of porcine chimeric embryos formed by micro-well aggregation. Chimeras were created by aggregating either two blastomeres originating from 2-cell embryos or two whole embryos, where embryos were produced...

  13. Coagulation efficiency and aggregate formation in marine phytoplankton

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Andersen, K.P.; Dam, H.G.

    1990-01-01

    Flocculation of phytoplankters into large, rapidly sinking aggregates has been implicated as a mechanism of vertical transport of phytoplankton to the sea floor which could have global significance. The formation rate of phytoplankton aggregates depends on the rate at which single cells collide...

  14. Preventing and De-Escalating Ethical Conflict: A Communication-Training Mediation Model.

    Science.gov (United States)

    Levin, Tomer T; Parker, Patricia A

    2015-01-01

    While ethical conflicts in the provision of healthcare are common, the current third-party mediator model is limited by a lack of expert ethical mediators, who are often not on site when conflict escalates. In order to improve clinical outcomes in situations such as conflicts at the end of life, we suggest that clinicians-physicians, nurses and social workers-be trained to prevent and de-escalate emerging conflicts. This can be achieved using a mediation model framed by a communication-training approach. A case example is presented and the model is discussed. The implication of this preventative/early intervention model for improving clinical outcomes, in particular end-of life conflict, is considered.

  15. The two faces of conscientiousness: duty and achievement striving in escalation of commitment dilemmas.

    Science.gov (United States)

    Moon, H

    2001-06-01

    The author proposes that 2 facets of conscientiousness, duty and achievement striving, affect decision makers in escalation of commitment dilemmas in opposing ways, thus masking the predictive ability of a broad measure of conscientiousness. It is proposed that duty is associated with an other-centered orientation and that achievement striving is associated with a self-centered orientation. Analyses of decisions from 360 respondents showed that duty was associated with a deescalation of commitment, achievement striving was associated with an escalation of commitment, and the broad measure of conscientiousness was unassociated with commitment. The author advocates the utility of understanding potential self-centered versus other-centered aspects of the criterion of interest when conducting personality-based research.

  16. Combined weekly paclitaxel and radiotherapy of stage III inoperable non-small-cell lung cancer (NSCLC). Results of a dose escalation study; Sequentielle Chemo- und Radiochemotherapie mit Paclitaxel/Carboplat und 3D-konformer Bestrahlung beim inoperablen nichtkleinzelligen Bronchialkarzinom. Ergebnisse einer Dosiseskalationsstudie

    Energy Technology Data Exchange (ETDEWEB)

    Willner, J.; Flentje, M. [Wuerzburg Univ. (Germany). Klinik und Poliklinik fuer Strahlentherapie; Schmidt, M.; Wirtz, H. [Wuerzburg Univ. (Germany). Abt. Pneumologie; Huber, R.M.; Fischer, R.; Lang, S. [Muenchen Univ. (Germany). Medizinische Klinik

    1997-11-01

    Purpose: Determination of the maximum tolerable dose of weekly paclitaxel infusions in combination with 3D-conformal radiotherapy in NSCLC. Evaluation of tumor response and side effects of this combined radio-chemotherapeutic approach. Materials and Methods: Patients with inoperable NSCLC, UICC-Stadium IIIA/B received 2 cycles of combined chemotherapy with paclitaxel (175 mg/m{sup 2}, 3-hour infusion)/carboplatin (AUC 5) followed by a combined radio-chemotherapy with 6 weekly paclitaxel infusions with dose escalation of paclitaxel from 40 to 80 mg/m{sup 2}. Radiotherapy was individually 3D-conformally planned. Primary tumor and regional lymphatics received a dose of 50 Gy (fractionation 2 Gy, 5 times per week), followed by a boost dose of 10 to 16 Gy to the primary tumor and involved lymph nodes (5 to 8 times 2 Gy). Toxicity of treatment was determined using WHO criteria. Results: Thirty-five patients have been treated until now. Two patients went off-study before completion of treatment for manifestation of distant metastases during initial chemotherapy and underwent palliative treatment, 30 patients are evaluable. The study has been closed in the paclitaxel 70 mg/m{sup 2} dose level. In 2 patients (level 50 mg/m{sup 2}) paclitaxel infusion was aborted for hypersensitivity reactions, 1 patient (60 mg/m{sup 2} paclitaxel) developed Grade III leucopenia and therefore received incomplete low-dose Taxol {sup trademark}, whereas radiotherapy of these 3 patients was completed. One patient (60 mg/m{sup 2}, 50 Gy) did not complete the treatment for a pneumonic infection, with Grade II esophagitis, Grade II leucopenia and a reduction in performance status. Three patients developed a Grade II esophagitis. Two patients in the paclitaxel 40 mg/m{sup 2} level and the 2 patients in the 70 mg level developed a Grade III esophagitis. Six patients developed clinical signs of radiation pneumonitis. Initial tumor response (PR and CR) was 87% (26/30). Survival rate at 12 months in 75

  17. p53 protein aggregation promotes platinum resistance in ovarian cancer.

    Science.gov (United States)

    Yang-Hartwich, Y; Soteras, M G; Lin, Z P; Holmberg, J; Sumi, N; Craveiro, V; Liang, M; Romanoff, E; Bingham, J; Garofalo, F; Alvero, A; Mor, G

    2015-07-01

    High-grade serous ovarian carcinoma (HGSOC), the most lethal gynecological cancer, often leads to chemoresistant diseases. The p53 protein is a key transcriptional factor regulating cellular homeostasis. A majority of HGSOCs have inactive p53 because of genetic mutations. However, genetic mutation is not the only cause of p53 inactivation. The aggregation of p53 protein has been discovered in different types of cancers and may be responsible for impairing the normal transcriptional activation and pro-apoptotic functions of p53. We demonstrated that in a unique population of HGSOC cancer cells with cancer stem cell properties, p53 protein aggregation is associated with p53 inactivation and platinum resistance. When these cancer stem cells differentiated into their chemosensitive progeny, they lost tumor-initiating capacity and p53 aggregates. In addition to the association of p53 aggregation and chemoresistance in HGSOC cells, we further demonstrated that the overexpression of a p53-positive regulator, p14ARF, inhibited MDM2-mediated p53 degradation and led to the imbalance of p53 turnover that promoted the formation of p53 aggregates. With in vitro and in vivo models, we demonstrated that the inhibition of p14ARF could suppress p53 aggregation and sensitize cancer cells to platinum treatment. Moreover, by two-dimensional gel electrophoresis and mass spectrometry we discovered that the aggregated p53 may function uniquely by interacting with proteins that are critical for cancer cell survival and tumor progression. Our findings help us understand the poor chemoresponse of a subset of HGSOC patients and suggest p53 aggregation as a new marker for chemoresistance. Our findings also suggest that inhibiting p53 aggregation can reactivate p53 pro-apoptotic function. Therefore, p53 aggregation is a potential therapeutic target for reversing chemoresistance. This is paramount for improving ovarian cancer patients' responses to chemotherapy, and thus increasing their

  18. Dose-Escalated Robotic SBRT for Stage I–II Prostate Cancer

    OpenAIRE

    Meier, Robert

    2015-01-01

    Stereotactic body radiotherapy (SBRT) is the precise external delivery of very high-dose radiotherapy to targets in the body, with treatment completed in one to five fractions. SBRT should be an ideal approach for organ-confined prostate cancer because (I) dose-escalation should yield improved rates of cancer control; (II) the unique radiobiology of prostate cancer favors hypofractionation; and (III) the conformal nature of SBRT minimizes high-dose radiation delivery to immediately adjacent o...

  19. Dose-Escalated Robotic SBRT for Stage I-II Prostate Cancer

    OpenAIRE

    Robert eMeier

    2015-01-01

    Abstract: Stereotactic body radiotherapy (SBRT) is the precise external delivery of very high-dose radiotherapy to targets in the body, with treatment completed in one to five fractions. SBRT should be an ideal approach for organ-confined prostate cancer because (I) dose escalation should yield improved rates of cancer control; (II) the unique radiobiology of prostate cancer favors hypofractionation and (III) the conformal nature of SBRT minimizes high-dose radiation delivery to immediately a...

  20. The social process of escalation: a promising focus for crisis management research

    Directory of Open Access Journals (Sweden)

    Bergström Johan

    2012-06-01

    Full Text Available Abstract Background This study identifies a promising, new focus for the crisis management research in the health care domain. After reviewing the literature on health care crisis management, there seems to be a knowledge-gap regarding organisational change and adaption, especially when health care situations goes from normal, to non-normal, to pathological and further into a state of emergency or crisis. Discussion Based on studies of escalating situations in obstetric care it is suggested that two theoretical perspectives (contingency theory and the idea of failure as a result of incomplete interaction tend to simplify the issue of escalation rather than attend to its complexities (including the various power relations among the stakeholders involved. However studying the process of escalation as inherently complex and social allows us to see the definition of a situation as normal or non-normal as an exercise of power in itself, rather than representing a putatively correct response to a particular emergency. Implications The concept of escalation, when treated this way, can help us further the analysis of clinical and institutional acts and competence. It can also turn our attention to some important elements in a class of social phenomenon, crises and emergencies, that so far have not received the attention they deserve. Focusing on organisational choreography, that interplay of potential factors such as power, professional identity, organisational accountability, and experience, is not only a promising focus for future naturalistic research but also for developing more pragmatic strategies that can enhance organisational coordination and response in complex events.

  1. Macroevolutionary patterns of glucosinolate defense and tests of defense-escalation and resource availability hypotheses.

    Science.gov (United States)

    Cacho, N Ivalú; Kliebenstein, Daniel J; Strauss, Sharon Y

    2015-11-01

    We explored macroevolutionary patterns of plant chemical defense in Streptanthus (Brassicaceae), tested for evolutionary escalation of defense, as predicted by Ehrlich and Raven's plant-herbivore coevolutionary arms-race hypothesis, and tested whether species inhabiting low-resource or harsh environments invest more in defense, as predicted by the resource availability hypothesis (RAH). We conducted phylogenetically explicit analyses using glucosinolate profiles, soil nutrient analyses, and microhabitat bareness estimates across 30 species of Streptanthus inhabiting varied environments and soils. We found weak to moderate phylogenetic signal in glucosinolate classes and no signal in total glucosinolate production; a trend toward evolutionary de-escalation in the numbers and diversity of glucosinolates, accompanied by an evolutionary increase in the proportion of aliphatic glucosinolates; some support for the RAH relative to soil macronutrients, but not relative to serpentine soil use; and that the number of glucosinolates increases with microhabitat bareness, which is associated with increased herbivory and drought. Weak phylogenetic signal in chemical defense has been observed in other plant systems. A more holistic approach incorporating other forms of defense might be necessary to confidently reject escalation of defense. That defense increases with microhabitat bareness supports the hypothesis that habitat bareness is an underappreciated selective force on plants in harsh environments.

  2. Mucosal healing in inflammatory bowel disease: Maintain orde-escalate therapy

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    In the past decade, thanks to the introduction of biologictherapies, a new therapeutic goal, mucosal healing(MH), has been introduced. MH is the expression of anarrest of disease progression, resulting in minor hospitalizations,surgeries, and prolonged clinical remission.MH may be achieved with several therapeutic strategiesreaching success rates up to 80% for both, ulcerativecolitis (UC) and Crohn's disease (CD). Various scoringsystems for UC and for the transmural CD, have beenproposed to standardize the definition of MH. Severalattempts have been undertaken to de-escalate therapyonce MH is achieved, thus, reducing the risk of adverseevents. In this review, we analysed the available studiesregarding the achievement of MH and the subsequenttreatment de-escalation according to disease typeand administered therapy, together with non-invasivemarkers proposed as predictors for relapse. The availabledata are not encouraging since de-escalation after theachievement of MH is followed by a high number ofclinical relapses reaching up to 50% within one year.Unclear is also another question, in case of combinationtherapies, which drug is more appropriate to stop, inorder to guarantee a durable remission. Predictorsof unfavourable outcome such as disease extension,perianal disease, or early onset disease appear to beinadequate to foresee behaviour of disease. Furtherstudies are warranted to investigate the role of histologichealing for the further course of disease.

  3. Terrorist attacks escalate in frequency and fatalities preceding highly lethal attacks.

    Directory of Open Access Journals (Sweden)

    Andy Martens

    Full Text Available Highly lethal terrorist attacks, which we define as those killing 21 or more people, account for 50% of the total number of people killed in all terrorist attacks combined, yet comprise only 3.5% of terrorist attacks. Given the disproportionate influence of these incidents, uncovering systematic patterns in attacks that precede and anticipate these highly lethal attacks may be of value for understanding attacks that exact a heavy toll on life. Here we examined whether the activity of terrorist groups escalates--both in the number of people killed per attack and in the frequency of attacks--leading up to highly lethal attacks. Analyses of terrorist attacks drawn from a state-of-the-art international terrorism database (The Global Terrorism Database showed evidence for both types of escalation leading up to highly lethal attacks, though complexities to the patterns emerged as well. These patterns of escalation do not emerge among terrorist groups that never commit a highly lethal attack.

  4. Inflammation Induces TDP-43 Mislocalization and Aggregation.

    Directory of Open Access Journals (Sweden)

    Ana Sofia Correia

    Full Text Available TAR DNA-binding protein 43 (TDP-43 is a major component in aggregates of ubiquitinated proteins in amyotrophic lateral sclerosis (ALS and frontotemporal lobar degeneration (FTLD. Here we report that lipopolysaccharide (LPS-induced inflammation can promote TDP-43 mislocalization and aggregation. In culture, microglia and astrocytes exhibited TDP-43 mislocalization after exposure to LPS. Likewise, treatment of the motoneuron-like NSC-34 cells with TNF-alpha (TNF-α increased the cytoplasmic levels of TDP-43. In addition, the chronic intraperitoneal injection of LPS at a dose of 1mg/kg in TDP-43(A315T transgenic mice exacerbated the pathological TDP-43 accumulation in the cytoplasm of spinal motor neurons and it enhanced the levels of TDP-43 aggregation. These results suggest that inflammation may contribute to development or exacerbation of TDP-43 proteinopathies in neurodegenerative disorders.

  5. Chaperone effects on prion and nonprion aggregates.

    Science.gov (United States)

    Rikhvanov, Eugene G; Romanova, Nina V; Chernoff, Yury O

    2007-01-01

    Exposure to high temperature or other stresses induces a synthesis of heat shock proteins. Many of these proteins are molecular chaperones, and some of them help cells to cope with heat-induced denaturation and aggregation of other proteins. In the last decade, chaperones have received increased attention in connection with their role in maintenance and propagation of the Saccharomyces cerevisiae prions, infectious or heritable agents transmitted at the protein level. Recent data suggest that functioning of the chaperones in reactivation of heat-damaged proteins and in propagation of prions is based on the same molecular mechanisms but may lead to different consequences depending on the type of aggregate. In both cases the concerted and balanced action of "chaperones' team," including Hsp104, Hsp70, Hsp40 and possibly other proteins, determines whether a misfolded protein is to be incorporated into an aggregate, rescued to the native state or targeted for degradation.

  6. Hydrophobic aggregation of ultrafine kaolinite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-ping; HU Yue-hua; LIU Run-Qing

    2008-01-01

    The hydrophobic aggregation of ultrafine kaolinite in cationic surfactant suspension was investigated by sedimentation test, zeta potential measurement and SEM observation. SEM images reveal that kaolinite particles show the self-aggregation of edge-face in acidic media, the aggregation of edge-face and edge-edge in neutral media, and the dispersion in alkaline media due to electrostatic repulsion. In the presence of the dodecylammonium acetate cationic surfactant and in neutral and alkaline suspension, the hydrophobic aggregation of face-face is demonstrated. The zeta potential of kaolinite increases with increasing the concentration of cationic surfactant. The small and loose aggregation at a low concentration but big and tight aggregation at a high concentration is presented At pH=7 alkyl quarterly amine salt CTAB has the best hydrophobic aggregation among three cationic surfactants, namely, dodecylammonium acetate, alkyl quarterly amine salts 1227 and CTAB.

  7. Absorption Spectra of Astaxanthin Aggregates

    CERN Document Server

    Olsina, Jan; Minofar, Babak; Polivka, Tomas; Mancal, Tomas

    2012-01-01

    Carotenoids in hydrated polar solvents form aggregates characterized by dramatic changes in their absorption spectra with respect to monomers. Here we analyze absorption spectra of aggregates of the carotenoid astaxanthin in hydrated dimethylsulfoxide. Depending on water content, two types of aggregates were produced: H-aggregates with absorption maximum around 390 nm, and J-aggregates with red-shifted absorption band peaking at wavelengths >550 nm. The large shifts with respect to absorption maximum of monomeric astaxanthin (470-495 nm depending on solvent) are caused by excitonic interaction between aggregated molecules. We applied molecular dynamics simulations to elucidate structure of astaxanthin dimer in water, and the resulting structure was used as a basis for calculations of absorption spectra. Absorption spectra of astaxanthin aggregates in hydrated dimethylsulfoxide were calculated using molecular exciton model with the resonance interaction energy between astaxanthin monomers constrained by semi-e...

  8. Structure and aggregation in model tetramethylurea solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Rini; Patey, G. N., E-mail: patey@chem.ubc.ca [Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1 (Canada)

    2014-08-14

    The structure of model aqueous tetramethylurea (TMU) solutions is investigated employing large-scale (32 000, 64 000 particles) molecular dynamics simulations. Results are reported for TMU mole fractions, X{sub t}, ranging from infinite dilution up to 0.07, and for two temperatures, 300 and 330 K. Two existing force fields for TMU-water solutions are considered. These are the GROMOS 53A6 united-atom TMU model combined with SPC/E water [TMU(GROMOS-UA)/W(SPC/E)], and the more frequently employed AMBER03 all-atom force field for TMU combined with the TIP3P water model [TMU(AMBER-AA)/W(TIP3P)]. It is shown that TMU has a tendency towards aggregation for both models considered, but the tendency is significantly stronger for the [TMU(AMBER-AA)/W(TIP3P)] force field. For this model signs of aggregation are detected at X{sub t} = 0.005, aggregation is a well established feature of the solution at X{sub t} = 0.02, and the aggregates increase further in size with increasing concentration. This is in agreement with at least some experimental studies, which report signals of aggregation in the low concentration regime. The TMU aggregates exhibit little structure and are simply loosely ordered, TMU-rich regions of solution. The [TMU(GROMOS-UA)/W(SPC/E)] model shows strong signs of aggregation only at higher concentrations (X{sub t} ≳ 0.04), and the aggregates appear more loosely ordered, and less well-defined than those occurring in the [TMU(AMBER-AA)/W(TIP3P)] system. For both models, TMU aggregation increases when the temperature is increased from 300 to 330 K, consistent with an underlying entropy driven, hydrophobic interaction mechanism. At X{sub t} = 0.07, the extra-molecular correlation length expected for microheterogeneous solutions has become comparable with the size of the simulation cell for both models considered, indicating that even the systems simulated here are sufficiently large only at low concentrations.

  9. Inhibitory effects of Tabebuia impetiginosa inner bark extract on platelet aggregation and vascular smooth muscle cell proliferation through suppressions of arachidonic acid liberation and ERK1/2 MAPK activation.

    Science.gov (United States)

    Son, Dong-Ju; Lim, Yong; Park, Young-Hyun; Chang, Sung-Keun; Yun, Yeo-Pyo; Hong, Jin-Tae; Takeoka, Gary R; Lee, Kwang-Geun; Lee, Sung-Eun; Kim, Mi-Ran; Kim, Jeong-Han; Park, Byeoung-Soo

    2006-11-03

    The antiplatelet and antiproliferative activities of extract of Tabebuia impetiginosa inner bark (taheebo) were investigated using washed rabbit platelets and cultured rat aortic vascular smooth muscle cells (VSMCs) in vitro. n-Hexane, chloroform and ethyl acetate fractions showed marked and selective inhibition of platelet aggregation induced by collagen and arachidonic acid (AA) in a dose-dependent manner. These fractions, especially the chloroform fraction, also significantly suppressed AA liberation induced by collagen in [(3)H]AA-labeled rabbit platelets. The fractions, especially the chloroform fraction, potently inhibited cell proliferation and DNA synthesis induced by platelet derived growth factor (PDGF)-BB, and inhibited the levels of phosphorylated extracellular signal regulated kinase (ERK1/2) mitogen activated protein kinase (MAPK) stimulated by PDGF-BB, in the same concentration range that inhibits VSMC proliferation and DNA synthesis.

  10. Escalating polypharmacy.

    Science.gov (United States)

    Gorard, D A

    2006-11-01

    New drug treatments, new indications for older drug treatments, lower thresholds for treating risk factors in preventative medicine, and an ageing population acquiring multiple pathologies all contribute to the development of polypharmacy. Longitudinal studies document the rise in prescribed medications, particularly in the elderly. The potential dangers of adverse drug reactions and interactions, poor adherence and confusion associated with ever-increasing polypharmacy are likely to worsen. Strategies to reduce prescribing will obviously decrease the dangers of polypharmacy. These include more considered prescribing when contemplating additions to patients' already lengthy prescription lists, and external reviews of medicine lists by a doctor or pharmacist. Despite such strategies, polypharmacy seems inevitable and considerations must be given to simplifying patients' multiple drug administrations using single-daily-dose regimens, fixed-dose combination pills, calendar-blister packaging and pill organizers.

  11. Developmental competence of porcine chimeric embryos produced by aggregation

    DEFF Research Database (Denmark)

    Li, Juan; Jakobsen, Jannik E.; Xiong, Qiang

    2015-01-01

    The purpose of our study was to compare the developmental competence and blastomere allocation of porcine chimeric embryos formed by micro-well aggregation. Chimeras were created by aggregating either two blastomeres originating from 2-cell embryos or two whole embryos, where embryos were produced...... either by parthenogenetic activation (PA) or handmade cloning (HMC). Results showed that the developmental competence of chimeric embryos, evaluated based on their blastocyst rate and total cell number per blastocyst, was increased when two whole 2-cell stage embryos (PA or HMC) were aggregated....... In comparison, when two blastomeres were aggregated, the developmental competence of the chimeric embryos decreased if the blastomeres were either from PA or from HMC embryos, but not if they were from different sources, i.e. one PA and one HMC blastomere. To evaluate the cell contribution in embryo formation...

  12. Dose Escalation and Healthcare Resource Use among Ulcerative Colitis Patients Treated with Adalimumab in English Hospitals: An Analysis of Real-World Data.

    Directory of Open Access Journals (Sweden)

    Christopher M Black

    Full Text Available To describe the real-world use of adalimumab for maintenance treatment of ulcerative colitis (UC and associated healthcare costs in English hospitals.Retrospective cohort study.Analysis of NHS Hospital Episode Statistics linked with pharmacy dispensing data in English hospitals.Adult UC patients receiving ≥240mg during adalimumab treatment induction, subsequently maintained on adalimumab.Frequency and pattern of adalimumab use and dose escalation during maintenance treatment and associated healthcare costs (prescriptions and hospital visits.191 UC patients completed adalimumab treatment induction. 83 (43.46% dose escalated during maintenance treatment by ≥100% (equivalent to weekly dosing (median time to dose escalation: 139 days. 56 patients (67.47% subsequently de-escalated by ≥50% (median time to dose de-escalation: 21 days. Mean all-cause healthcare costs for all patients ≤12 months of index were £13,892. Dose escalators incurred greater mean healthcare costs than non-escalators ≤12 months of index (£14,596 vs. £13,351. Prescriptions accounted for 96.49% of UC-related healthcare costs (£11,090 of £11,494 in all patients.Within the cohort, 43.46% of UC patients escalated their adalimumab dose by ≥100% and incurred greater costs than non-escalators. The apparent underestimation of adalimumab dose escalation in previous studies may have resulted in underestimated costs in healthcare systems.

  13. Disaggregases, molecular chaperones that resolubilize protein aggregates

    Directory of Open Access Journals (Sweden)

    David Z. Mokry

    2015-08-01

    Full Text Available The process of folding is a seminal event in the life of a protein, as it is essential for proper protein function and therefore cell physiology. Inappropriate folding, or misfolding, can not only lead to loss of function, but also to the formation of protein aggregates, an insoluble association of polypeptides that harm cell physiology, either by themselves or in the process of formation. Several biological processes have evolved to prevent and eliminate the existence of non-functional and amyloidogenic aggregates, as they are associated with several human pathologies. Molecular chaperones and heat shock proteins are specialized in controlling the quality of the proteins in the cell, specifically by aiding proper folding, and dissolution and clearance of already formed protein aggregates. The latter is a function of disaggregases, mainly represented by the ClpB/Hsp104 subfamily of molecular chaperones, that are ubiquitous in all organisms but, surprisingly, have no orthologs in the cytosol of metazoan cells. This review aims to describe the characteristics of disaggregases and to discuss the function of yeast Hsp104, a disaggregase that is also involved in prion propagation and inheritance.

  14. HecA, a member of a class of adhesins produced by diverse pathogenic bacteria, contributes to the attachment, aggregation, epidermal cell killing, and virulence phenotypes of Erwinia chrysanthemi EC16 on Nicotiana clevelandii seedlings.

    Science.gov (United States)

    Rojas, Clemencia M; Ham, Jong Hyun; Deng, Wen-Ling; Doyle, Jeff J; Collmer, Alan

    2002-10-01

    Erwinia chrysanthemi is representative of a broad class of bacterial pathogens that are capable of inducing necrosis in plants. The E. chrysanthemi EC16 hecA gene predicts a 3,850-aa member of the Bordetella pertussis filamentous hemagglutinin family of adhesins. A hecATn7 mutant was reduced in virulence on Nicotiana clevelandii seedlings after inoculation without wounding. Epifluorescence and confocal laser-scanning microscopy observations of hecA and wild-type cells expressing the green fluorescent protein revealed that the mutant is reduced in its ability to attach and then form aggregates on leaves and to cause an aggregate-associated killing of epidermal cells. Cell killing also depended on production of the major pectate lyase isozymes and the type II, but not the type III, secretion pathway in E. chrysanthemi. HecA homologs were found in bacterial pathogens of plants and animals and appear to be unique to pathogens and universal in necrogenic plant pathogens. Phylogenetic comparison of the conserved two-partner secretion domains in the proteins and the 16S rRNA sequences in respective bacteria revealed the two datasets to be fundamentally incongruent, suggesting horizontal acquisition of these genes. Furthermore, hecA and its two homologs in Yersinia pestis had a G+C content that was 10% higher than that of their genomes and similar to that of plant pathogenic Ralstonia, Xylella, and Pseudomonas spp. Our data suggest that filamentous hemagglutinin-like adhesins are broadly important virulence factors in both plant and animal pathogens.

  15. Radiobiological Determination of Dose Escalation and Normal Tissue Toxicity in Definitive Chemoradiation Therapy for Esophageal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Samantha, E-mail: Samantha.warren@oncology.ox.ac.uk [Department of Oncology, Gray Institute of Radiation Oncology and Biology, University of Oxford, Oxford (United Kingdom); Partridge, Mike [Department of Oncology, Gray Institute of Radiation Oncology and Biology, University of Oxford, Oxford (United Kingdom); Carrington, Rhys [Velindre Cancer Centre, Velindre Hospital, Cardiff (United Kingdom); Hurt, Chris [Wales Cancer Trials Unit, School of Medicine, Heath Park, Cardiff (United Kingdom); Crosby, Thomas [Velindre Cancer Centre, Velindre Hospital, Cardiff (United Kingdom); Hawkins, Maria A. [Department of Oncology, Gray Institute of Radiation Oncology and Biology, University of Oxford, Oxford (United Kingdom)

    2014-10-01

    Purpose: This study investigated the trade-off in tumor coverage and organ-at-risk sparing when applying dose escalation for concurrent chemoradiation therapy (CRT) of mid-esophageal cancer, using radiobiological modeling to estimate local control and normal tissue toxicity. Methods and Materials: Twenty-one patients with mid-esophageal cancer were selected from the SCOPE1 database (International Standard Randomised Controlled Trials number 47718479), with a mean planning target volume (PTV) of 327 cm{sup 3}. A boost volume, PTV2 (GTV + 0.5 cm margin), was created. Radiobiological modeling of tumor control probability (TCP) estimated the dose required for a clinically significant (+20%) increase in local control as 62.5 Gy/25 fractions. A RapidArc (RA) plan with a simultaneously integrated boost (SIB) to PTV2 (RA{sub 62.5}) was compared to a standard dose plan of 50 Gy/25 fractions (RA{sub 50}). Dose-volume metrics and estimates of normal tissue complication probability (NTCP) for heart and lungs were compared. Results: Clinically acceptable dose escalation was feasible for 16 of 21 patients, with significant gains (>18%) in tumor control from 38.2% (RA{sub 50}) to 56.3% (RA{sub 62.5}), and only a small increase in predicted toxicity: median heart NTCP 4.4% (RA{sub 50}) versus 5.6% (RA{sub 62.5}) P<.001 and median lung NTCP 6.5% (RA{sub 50}) versus 7.5% (RA{sub 62.5}) P<.001. Conclusions: Dose escalation to the GTV to improve local control is possible when overlap between PTV and organ-at-risk (<8% heart volume and <2.5% lung volume overlap for this study) generates only negligible increase in lung or heart toxicity. These predictions from radiobiological modeling should be tested in future clinical trials.

  16. Validation of treatment escalation as a definition of atopic eczema flares.

    Directory of Open Access Journals (Sweden)

    Kim S Thomas

    Full Text Available Atopic eczema (AE is a chronic disease with flares and remissions. Long-term control of AE flares has been identified as a core outcome domain for AE trials. However, it is unclear how flares should be defined and measured.To validate two concepts of AE flares based on daily reports of topical medication use: (i escalation of treatment and (ii days of topical anti-inflammatory medication use (topical corticosteroids and/or calcineurin inhibitors.Data from two published AE studies (studies A (n=336 and B (n=60 were analysed separately. Validity and feasibility of flare definitions were assessed using daily global bother (scale 0 to 10 as the reference standard. Intra-class correlations were reported for continuous variables, and odds ratios and area under the receiver operator characteristic (ROC curve for binary outcome measures.Good agreement was found between both AE flare definitions and change in global bother: area under the ROC curve for treatment escalation of 0.70 and 0.73 in studies A and B respectively, and area under the ROC curve of 0.69 for topical anti-inflammatory medication use (Study A only. Significant positive relationships were found between validated severity scales (POEM, SASSAD, TIS and the duration of AE flares occurring in the previous week - POEM and SASSAD rose by half a point for each unit increase in number of days in flare. Smaller increases were observed on the TIS scale. Completeness of daily diaries was 95% for Study A and 60% for Study B over 16 weeks.Both definitions were good proxy indicators of AE flares. We found no evidence that 'escalation of treatment' was a better measure of AE flares than 'use of topical anti-inflammatory medications'. Capturing disease flares in AE trials through daily recording of medication use is feasible and appears to be a good indicator of long-term control.Current Controlled Trials ISRCTN71423189 (Study A.

  17. Microbial properties of soil aggregates created by earthworms and other factors: spherical and prismatic soil aggregates from unreclaimed post-mining sites

    Energy Technology Data Exchange (ETDEWEB)

    Frouz, J.; Kristufek, V.; Liveckova, M.; van Loo, D.; Jacobs, P.; Van Hoorebeke, L. [Charles University of Prague, Prague (Czech Republic). Inst. of Environmental Studies

    2011-01-15

    Soil aggregates between 2 and 5 mm from 35- and 45-year-old unreclaimed post-mining sites near Sokolov (Czech Republic) were divided into two groups: spherical and prismatic. X-ray tomography indicated that prismatic aggregates consisted of fragments of claystone bonded together by amorphous clay and roots while spherical aggregates consisted of a clay matrix and organic fragments of various sizes. Prismatic aggregates were presumed to be formed by plant roots and physical processes during weathering of Tertiary mudstone, while earthworms were presumed to contribute to the formation of spherical aggregates. The effects of drying and rewetting and glucose addition on microbial respiration, microbial biomass, and counts of bacteria in these aggregates were determined. Spherical aggregates contained a greater percentage of C and N and a higher C-to-N ratio than prismatic ones. The C content of the particulate organic matter was also higher in the spherical than in the prismatic aggregates. Although spherical aggregates had a higher microbial respiration and biomass, the growth of microbial biomass in spherical aggregates was negatively correlated with initial microbial biomass, indicating competition between bacteria. Specific respiration was negatively correlated with microbial biomass. Direct counts of bacteria were higher in spherical than in prismatic aggregates. Bacterial numbers were more stable in the center than in the surface layers of the aggregates. Transmission electron microscopy indicated that bacteria often occurred as individual cells in prismatic aggregates but as small clusters of cells in spherical aggregates. Ratios of colony forming units (cultivatable bacteria) to direct counts were higher in spherical than in prismatic aggregates. Spherical aggregates also contained faster growing bacteria.

  18. Successful pregnancy outcome in paroxysmal nocturnal hemoglobinuria (PNH following escalated eculizumab dosing to control breakthrough hemolysis

    Directory of Open Access Journals (Sweden)

    Ruby Sharma

    2015-01-01

    Full Text Available Pregnancy in women with paroxysmal nocturnal hemoglobinuria (PNH is associated with increased maternal and fetal morbidity and mortality. There is limited published experience regarding therapy of PNH during pregnancy. We describe a case of a 30 year old female with hypoplastic myelodysplastic syndrome and PNH. After two years of treatment with eculizumab, she became pregnant. She developed breakthrough hemolysis at 20 weeks gestation. Pharmacokinetic and pharmacodynamic studies demonstrated a subtherapeutic eculizumab level with absence of complement blockade. Escalation of her eculizumab dose successfully controlled hemolysis and restored therapeutic eculizumab level and activity. She delivered a healthy baby at 36 weeks.

  19. Novel aspects of platelet aggregation

    Directory of Open Access Journals (Sweden)

    Roka-Moya Y. M.

    2014-01-01

    Full Text Available The platelet aggregation is an important process, which is critical for the hemostatic plug formation and thrombosis. Recent studies have shown that the platelet aggregation is more complex and dynamic than it was previously thought. There are several mechanisms that can initiate the platelet aggregation and each of them operates under specific conditions in vivo. At the same time, the influence of certain plasma proteins on this process should be considered. This review intends to summarize the recent data concerning the adhesive molecules and their receptors, which provide the platelet aggregation under different conditions.

  20. Fractal Aggregation Under Rotation

    Institute of Scientific and Technical Information of China (English)

    WU Feng-Min; WU Li-Li; LU Hang-Jun; LI Qiao-Wen; YE Gao-Xiang

    2004-01-01

    By means of the Monte Carlo simulation, a fractal growth model is introduced to describe diffusion-limited aggregation (DLA) under rotation. Patterns which are different from the classical DLA model are observed and the fractal dimension of such clusters is calculated. It is found that the pattern of the clusters and their fractal dimension depend strongly on the rotation velocity of the diffusing particle. Our results indicate the transition from fractal to non-fractal behavior of growing cluster with increasing rotation velocity, i.e. for small enough angular velocity ω the fractal dimension decreases with increasing ω, but then, with increasing rotation velocity, the fractal dimension increases and the cluster becomes compact and tends to non-fractal.

  1. Fractal Aggregation Under Rotation

    Institute of Scientific and Technical Information of China (English)

    WUFeng-Min; WULi-Li; LUHang-Jun; LIQiao-Wen; YEGao-Xiang

    2004-01-01

    By means of the Monte Carlo simulation, a fractal growth model is introduced to describe diffusion-limited aggregation (DLA) under rotation. Patterns which are different from the classical DLA model are observed and the fractal dimension of such clusters is calculated. It is found that the pattern of the clusters and their fractal dimension depend strongly on the rotation velocity of the diffusing particle. Our results indicate the transition from fractal to non-fractal behavior of growing cluster with increasing rotation velocity, i.e. for small enough angular velocity ω; thefractal dimension decreases with increasing ω;, but then, with increasing rotation velocity, the fractal dimension increases and the cluster becomes compact and tends to non-fractal.

  2. Copper-triggered aggregation of ubiquitin.

    Science.gov (United States)

    Arnesano, Fabio; Scintilla, Simone; Calò, Vincenza; Bonfrate, Elena; Ingrosso, Chiara; Losacco, Maurizio; Pellegrino, Teresa; Rizzarelli, Enrico; Natile, Giovanni

    2009-09-16

    Neurodegenerative disorders share common features comprising aggregation of misfolded proteins, failure of the ubiquitin-proteasome system, and increased levels of metal ions in the brain. Protein aggregates within affected cells often contain ubiquitin, however no report has focused on the aggregation propensity of this protein. Recently it was shown that copper, differently from zinc, nickel, aluminum, or cadmium, compromises ubiquitin stability and binds to the N-terminus with 0.1 micromolar affinity. This paper addresses the role of copper upon ubiquitin aggregation. In water, incubation with Cu(II) leads to formation of spherical particles that can progress from dimers to larger conglomerates. These spherical oligomers are SDS-resistant and are destroyed upon Cu(II) chelation or reduction to Cu(I). In water/trifluoroethanol (80:20, v/v), a mimic of the local decrease in dielectric constant experienced in proximity to a membrane surface, ubiquitin incubation with Cu(II) causes time-dependent changes in circular dichroism and Fourier-transform infrared spectra, indicative of increasing beta-sheet content. Analysis by atomic force and transmission electron microscopy reveals, in the given order, formation of spherical particles consistent with the size of early oligomers detected by gel electrophoresis, clustering of these particles in straight and curved chains, formation of ring structures, growth of trigonal branches from the rings, coalescence of the trigonal branched structures in a network. Notably, none of these ubiquitin aggregates was positive to tests for amyloid and Cu(II) chelation or reduction produced aggregate disassembly. The early formed Cu(II)-stabilized spherical oligomers, when reconstituted in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) liposomes and in POPC planar bilayers, form annular and pore-like structures, respectively, which are common to several neurodegenerative disorders including Parkinson's, Alzheimer's, amyotrophic

  3. Copper-triggered aggregation of ubiquitin.

    Directory of Open Access Journals (Sweden)

    Fabio Arnesano

    Full Text Available Neurodegenerative disorders share common features comprising aggregation of misfolded proteins, failure of the ubiquitin-proteasome system, and increased levels of metal ions in the brain. Protein aggregates within affected cells often contain ubiquitin, however no report has focused on the aggregation propensity of this protein. Recently it was shown that copper, differently from zinc, nickel, aluminum, or cadmium, compromises ubiquitin stability and binds to the N-terminus with 0.1 micromolar affinity. This paper addresses the role of copper upon ubiquitin aggregation. In water, incubation with Cu(II leads to formation of spherical particles that can progress from dimers to larger conglomerates. These spherical oligomers are SDS-resistant and are destroyed upon Cu(II chelation or reduction to Cu(I. In water/trifluoroethanol (80:20, v/v, a mimic of the local decrease in dielectric constant experienced in proximity to a membrane surface, ubiquitin incubation with Cu(II causes time-dependent changes in circular dichroism and Fourier-transform infrared spectra, indicative of increasing beta-sheet content. Analysis by atomic force and transmission electron microscopy reveals, in the given order, formation of spherical particles consistent with the size of early oligomers detected by gel electrophoresis, clustering of these particles in straight and curved chains, formation of ring structures, growth of trigonal branches from the rings, coalescence of the trigonal branched structures in a network. Notably, none of these ubiquitin aggregates was positive to tests for amyloid and Cu(II chelation or reduction produced aggregate disassembly. The early formed Cu(II-stabilized spherical oligomers, when reconstituted in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC liposomes and in POPC planar bilayers, form annular and pore-like structures, respectively, which are common to several neurodegenerative disorders including Parkinson's, Alzheimer

  4. Aggregation of MBP in chronic demyelination

    Science.gov (United States)

    Frid, Kati; Einstein, Ofira; Friedman-Levi, Yael; Binyamin, Orli; Ben-Hur, Tamir; Gabizon, Ruth

    2015-01-01

    Objectives Misfolding of key disease proteins to an insoluble state is associated with most neurodegenerative conditions, such as prion, Parkinson, and Alzheimer’s diseases. In this work, and by studying animal models of multiple sclerosis, we asked whether this is also the case for myelin basic protein (MBP) in the late and neurodegenerative phases of demyelinating diseases. Methods To this effect, we tested whether MBP, an essential myelin component, present prion-like properties in animal models of MS, as is the case for Cuprizone-induced chronic demyelination or chronic phases of Experimental Autoimmune Encephalomyelitis (EAE). Results We show here that while total levels of MBP were not reduced following extensive demyelination, part of these molecules accumulated thereafter as aggregates inside oligodendrocytes or around neuronal cells. In chronic EAE, MBP precipitated concomitantly with Tau, a marker of diverse neurodegenerative conditions, including MS. Most important, analysis of fractions from Triton X-100 floatation gradients suggest that the lipid composition of brain membranes in chronic EAE differs significantly from that of naïve mice, an effect which may relate to oxidative insults and subsequently prevent the appropriate insertion and compaction of new MBP in the myelin sheath, thereby causing its misfolding and aggregation. Interpretation Prion-like aggregation of MBP following chronic demyelination may result from an aberrant lipid composition accompanying this pathological status. Such aggregation of MBP may contribute to neuronal damage that occurs in the progressive phase of MS. PMID:26273684

  5. SU-E-T-622: Identification and Improvement of Patients Eligible for Dose Escalation with Matched Plans

    Energy Technology Data Exchange (ETDEWEB)

    Bush, K; Holcombe, C; Kapp, D; Buyyounouski, M; Hancock, S; Xing, L; Atwood, T; King, M [Department of Radiation Oncology, Stanford School of Medicine, Stanford, CA (United States)

    2014-06-15

    Purpose: Radiation-therapy dose-escalation beyond 80Gy may improve tumor control rates for patients with localized prostate cancer. Since toxicity remains a concern, treatment planners must achieve dose-escalation while still adhering to dose-constraints for surrounding structures. Patientmatching is a machine-learning technique that identifies prior patients that dosimetrically match DVH parameters of target volumes and critical structures prior to actual treatment planning. We evaluated the feasibility of patient-matching in (1)identifying candidates for safe dose-escalation; and (2)improving DVH parameters for critical structures in actual dose-escalated plans. Methods: We analyzed DVH parameters from 319 historical treatment plans to determine which plans could achieve dose-escalation (8640cGy) without exceeding Zelefsky dose-constraints (rectal and bladder V47Gy<53%, and V75.6Gy<30%, max-point dose to rectum of 8550cGy, max dose to PTV< 9504cGy). We then estimated the percentage of cases that could achieve safe dose-escalation using software that enables patient matching (QuickMatch, Siris Medical, Mountain View, CA). We then replanned a case that had violated DVH constraints with DVH parameters from patient matching, in order to determine whether this previously unacceptable plan could be made eligible with this automated technique. Results: Patient-matching improved the percentage of patients eligible for dose-escalation from 40% to 63% (p=4.7e-4, t-test). Using a commercial optimizer augmented with patient-matching, we demonstrated a case where patient-matching improved the toxicity-profile such that dose-escalation would have been possible; this plan was rapidly achieved using patientmatching software. In this patient, all lower-dose constraints were met with both the denovo and patient-matching plan. In the patient-matching plan, maximum dose to the rectum was 8385cGy, while the denovo plan failed to meet the maximum rectal constraint at 8571c

  6. Daily-diary Evaluated Side Effects of Dose-escalation Radiotherapy of Prostate Cancer Using the Stereotactic Beamcath Technique

    Energy Technology Data Exchange (ETDEWEB)

    Fransson, Per; Bergstroem, Per; Loefroth, Per-Olov; Franzen, Lars; Henriksson, Roger; Widmark, Anders [Umeaa Univ. (Sweden). Dept. of Radiation Sciences

    2003-06-01

    The aim of this study was to evaluate self-assessed late side effects in patients with prostate cancer treated with frameless stereotactic dose-escalation radiotherapy using BeamCath, a new technique that has been developed for accurate positioning of the prostate at treatment set-up, and in which a specially designed urethral catheter containing high-density fiducial markers is used. The method was tested in the first 104 patients in a Scandinavian dose-escalation study with doses up to 76 Gy. Side effects were reported in a daily diary and evaluated at the start of treatment (baseline) and at 1-year follow-up. The patients were compared with those treated with conventional (n=53) and conformal techniques (n=175). Dose-escalation radiotherapy (76 Gy) decreased urinary frequency, urgency and starting problems at 1-year in comparison with baseline. The dose-escalation therapy did not induce any increase in gastrointestinal side effects in comparison with the effect of conformal therapy h70 Gy at the 1-year follow-up, apart from a slight increase in rectal mucus in the 76 Gy group. All groups, except patients receiving the 74 Gy with smaller fields, reported a slight increase in gastrointestinal toxicity at 1-year compared with baseline. Dose-escalation radiotherapy of prostate cancer using the BeamCath technique did not induce any significant increase in late side effects in comparison with conformal technique.

  7. Toxicity-dependent feasibility bounds for the escalation with overdose control approach in phase I cancer trials.

    Science.gov (United States)

    Wheeler, Graham M; Sweeting, Michael J; Mander, Adrian P

    2017-03-15

    Phase I trials of anti-cancer therapies aim to identify a maximum tolerated dose (MTD), defined as the dose that causes unacceptable toxicity in a target proportion of patients. Both rule-based and model-based methods have been proposed for MTD recommendation. The escalation with overdose control (EWOC) approach is a model-based design where the dose assigned to the next patient is one that, given all available data, has a posterior probability of exceeding the MTD equal to a pre-specified value known as the feasibility bound. The aim is to conservatively dose-escalate and approach the MTD, avoiding severe overdosing early on in a trial. The EWOC approach has been applied in practice with the feasibility bound either fixed or varying throughout a trial, yet some of the methods may recommend incoherent dose-escalation, that is, an increase in dose after observing severe toxicity at the current dose. We present examples where varying feasibility bounds have been used in practice, and propose a toxicity-dependent feasibility bound approach that guarantees coherent dose-escalation and incorporates the desirable features of other EWOC approaches. We show via detailed simulation studies that the toxicity-dependent feasibility bound approach provides improved MTD recommendation properties to the original EWOC approach for both discrete and continuous doses across most dose-toxicity scenarios, with comparable performance to other approaches without recommending incoherent dose escalation. © 2017 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

  8. 基于金纳米聚集体的核壳型SERS探针及其细胞内应用%Preparation of Silica-coated Aggregated Gold Nanoparticles and Their SERS Performance in Living Cells

    Institute of Scientific and Technical Information of China (English)

    杨晶; 王著元; 张若虎; 宋春元; 李锦; 高文成; 崔一平

    2011-01-01

    利用金纳米粒子的聚集体作为表面增强拉曼散射(Surface enhanced Raman scattering,SERS)的增强基底,合成了一种二氧化硅包裹的核壳型SERS探针,并成功将该探针应用于活细胞的SERS光谱探测.实验中利用4-巯基苯甲酸(4-mercaptobenzoicacid,4MBA)作为拉曼标记物,并讨论了其在诱导金纳米粒子的聚集过程中的作用.通过包二氧化硅外壳来实现对金纳米颗粒聚集程度的控制,保持并优化了该探针的SERS活性.同时,通过在金纳米颗粒外包裹一层二氧化硅外壳,该SERS探针的化学稳定性和生物兼容性得到了很大的提高.利用紫外-可见吸收光谱仪以及透射电子显微镜研究了该探针中金纳米颗粒的聚集程度以及核壳结构的形貌.实验结果表明该探针在活细胞内具有很好的SERS灵敏度,并且生物兼容性好,可以进一步用于细胞内生理活动监测.%We present a novel core/shell SERS(surface enhanced Raman scattering) probe based on silica-coated gold nanoaggregates and its SERS application in living cells.It is found that the chemical stability and biocompatibility can be greatly improved by coating the gold nanoparticles with a layer of silica.In our experiments,4MBA(4-mercaptobenzoicacid) is used not only as a Raman reporter,but also an aggregation agent.By coating the gold nanoparticles with the silica shell,the aggregation of gold nanoparticles can be controlled to optimize the SERS activity.TEM images and UV-Vis spectra were em-ployed to investigate the core-shell structure of the probe and the aggregation degree of gold nanoparticles.The results exhibit the strong performance of SERS sensitivity and biocompatibility of the probe in living HeLa and SKBR3 cells,indicating its attraction in further application in intracellular environment.

  9. Priming by Chemokines Restricts Lateral Mobility of the Adhesion Receptor LFA-1 and Restores Adhesion to ICAM-1 Nano-Aggregates on Human Mature Dendritic Cells

    NARCIS (Netherlands)

    Borgman, K.J.; Zanten, T.S. van; Manzo, C.; Cabezon, R.; Cambi, A.; Benitez-Ribas, D.; Garcia-Parajo, M.F.

    2014-01-01

    LFA-1 is a leukocyte specific beta2 integrin that plays a major role in regulating adhesion and migration of different immune cells. Recent data suggest that LFA-1 on mature dendritic cells (mDCs) may function as a chemokine-inducible anchor during homing of DCs through the afferent lymphatics into

  10. Priming by Chemokines Restricts Lateral Mobility of the Adhesion Receptor LFA-1 and Restores Adhesion to ICAM-1 Nano-Aggregates on Human Mature Dendritic Cells

    NARCIS (Netherlands)

    Borgman, K.J.; Zanten, van T.S.; Manzo, C.; Cabezon, R.; Cambi, A.; Benitez-Ribas, D.; Garcia Parajo, M.F.

    2014-01-01

    LFA-1 is a leukocyte specific β2 integrin that plays a major role in regulating adhesion and migration of different immune cells. Recent data suggest that LFA-1 on mature dendritic cells (mDCs) may function as a chemokine-inducible anchor during homing of DCs through the afferent lymphatics into the

  11. Stairs or escalator? Using theories of persuasion and motivation to facilitate healthy decision making.

    Science.gov (United States)

    Suri, Gaurav; Sheppes, Gal; Leslie, Sara; Gross, James J

    2014-12-01

    To encourage an increase in daily activity, researchers have tried a variety of health-related communications, but with mixed results. In the present research-using the stair escalator choice context-we examined predictions derived from the Heuristic Systematic Model (HSM), Self Determination Theory (SDT), and related theories. Specifically, we tested whether (as predicted by HSM) signs that encourage heuristic processing ("Take the Stairs") would have greatest impact when placed at the stair/escalator point of choice (when processing time is limited), whereas signs that encourage systematic processing ("Will You Take the Stairs?") would have greatest impact when placed at some distance from the point of choice (when processing time is less limited). We also tested whether (as predicted by SDT) messages promoting autonomy would be more likely to result in sustained motivated behavior (i.e., stair taking at subsequent uncued choice points) than messages that use commands. A series of studies involving more than 9,000 pedestrians provided support for these predictions.

  12. EFFECT OF TARIFF ESCALATION ON GHANAIAN COCOA EXPORTS: AN EMPIRICAL PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Ahmed Abdul Aziz

    2017-01-01

    Full Text Available This study analyses the effects of tariff escalation on Ghanaian cocoa exports in four importing markets: USA, EU, Japan and Malaysia. The study estimates nominal and effective protection coefficients in these markets based on ad-valorem equivalent of applied and bound specific tariffs. Results revealed that, effective protection exists in the Japanese and Malaysian cocoa industries at different stages of processing on both bound and applied tariffs. In contrast, the USA and the EU do not effectively protect their cocoa industries, thus, no tariff escalation on applied tariffs against cocoa imports from Ghana. This study concludes that from a static effect, higher tariffs do have a negative consequence on Ghanaian cocoa exports in these importing countries. From a dynamic perspective however, the relationship between tariff structures in these importing countries and Ghanaian cocoa exports is somewhat ambiguous and each situation has to be viewed on their own merit. A complete elimination of tariffs as a form of trade barrier on Ghanaian cocoa exports does not necessarily imply that Ghana could easily increase its exports of value added cocoa.

  13. Ion Elevators and Escalators in Multilevel Structures for Lossless Ion Manipulations

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, Yehia M.; Hamid, Ahmed M.; Cox, Jonathan T.; Garimella, Sandilya V. B.; Smith, Richard D.

    2017-01-19

    We describe two approaches based upon ion ‘elevator’ and ‘escalator’ components that allow moving ions to different levels in structures for lossless ion manipulations (SLIM). Guided by ion motion simulations we designed elevator and escalator components providing essentially lossless transmission in multi-level designs based upon ion current measurements. The ion elevator design allowed ions to efficiently bridge a 4 mm gap between levels. The component was integrated in a SLIM and coupled to a QTOF mass spectrometer using an ion funnel interface to evaluate the m/z range transmitted as compared to transmission within a level (e.g. in a linear section). Mass spectra for singly-charged ions of m/z 600-2700 produced similar mass spectra for both elevator and straight (linear motion) components. In the ion escalator design, traveling waves (TW) were utilized to transport ions efficiently between two SLIM levels. Ion current measurements and ion mobility (IM) spectrometry analysis illustrated that ions can be transported between TW-SLIM levels with no significant loss of either ions or IM resolution. These developments provide a path for the development of multilevel designs providing e.g. much longer IM path lengths, more compact designs, and the implementation of much more complex SLIM devices in which e.g. different levels may operate at different temperatures or with different gases.

  14. Terrorist Attacks Escalate in Frequency and Fatalities Preceding Highly Lethal Attacks

    Science.gov (United States)

    Martens, Andy; Sainudiin, Raazesh; Sibley, Chris G.; Schimel, Jeff; Webber, David

    2014-01-01

    Highly lethal terrorist attacks, which we define as those killing 21 or more people, account for 50% of the total number of people killed in all terrorist attacks combined, yet comprise only 3.5% of terrorist attacks. Given the disproportionate influence of these incidents, uncovering systematic patterns in attacks that precede and anticipate these highly lethal attacks may be of value for understanding attacks that exact a heavy toll on life. Here we examined whether the activity of terrorist groups escalates–both in the number of people killed per attack and in the frequency of attacks–leading up to highly lethal attacks. Analyses of terrorist attacks drawn from a state-of-the-art international terrorism database (The Global Terrorism Database) showed evidence for both types of escalation leading up to highly lethal attacks, though complexities to the patterns emerged as well. These patterns of escalation do not emerge among terrorist groups that never commit a highly lethal attack. PMID:24755753

  15. Escalation with Overdose Control is More Efficient and Safer than Accelerated Titration for Dose Finding

    Directory of Open Access Journals (Sweden)

    André Rogatko

    2015-07-01

    Full Text Available The standard 3 + 3 or “modified Fibonacci” up-and-down (MF-UD method of dose escalation is by far the most used design in dose-finding cancer trials. However, MF-UD has always shown inferior performance when compared with its competitors regarding number of patients treated at optimal doses. A consequence of using less effective designs is that more patients are treated with doses outside the therapeutic window. In June 2012, the U S Food and Drug Administration (FDA rejected the proposal to use Escalation with Overdose Control (EWOC, an established dose-finding method which has been extensively used in FDA-approved first in human trials and imposed a variation of the MF-UD, known as accelerated titration (AT design. This event motivated us to perform an extensive simulation study comparing the operating characteristics of AT and EWOC. We show that the AT design has poor operating characteristics relative to three versions of EWOC under several practical scenarios. From the clinical investigator’s perspective, lower bias and mean square error make EWOC designs preferable than AT designs without compromising safety. From a patient’s perspective, uniformly higher proportion of patients receiving doses within an optimal range of the true MTD makes EWOC designs preferable than AT designs.

  16. Chronic CRF1 receptor blockade reduces heroin intake escalation and dependence-induced hyperalgesia.

    Science.gov (United States)

    Park, Paula E; Schlosburg, Joel E; Vendruscolo, Leandro F; Schulteis, Gery; Edwards, Scott; Koob, George F

    2015-03-01

    Opioids represent effective drugs for the relief of pain, yet chronic opioid use often leads to a state of increased sensitivity to pain that is exacerbated during withdrawal. A sensitization of pain-related negative affect has been hypothesized to closely interact with addiction mechanisms. Neuro-adaptive changes occur as a consequence of excessive opioid exposure, including a recruitment of corticotropin-releasing factor (CRF) and norepinephrine (NE) brain stress systems. To better understand the mechanisms underlying the transition to dependence, we determined the effects of functional antagonism within these two systems on hyperalgesia-like behavior during heroin withdrawal utilizing models of both acute and chronic dependence. We found that passive or self-administered heroin produced a significant mechanical hypersensitivity. During acute opioid dependence, systemic administration of the CRF1 receptor antagonist MPZP (20 mg/kg) alleviated withdrawal-induced mechanical hypersensitivity. In contrast, several functional adrenergic system antagonists (clonidine, prazosin, propranolol) failed to alter mechanical hypersensitivity in this state. We then determined the effects of chronic MPZP or clonidine treatment on extended access heroin self-administration and found that MPZP, but not clonidine, attenuated escalation of heroin intake, whereas both drugs alleviated chronic dependence-associated hyperalgesia. These findings suggest that an early potentiation of CRF signaling occurs following opioid exposure that begins to drive both opioid-induced hyperalgesia and eventually intake escalation.

  17. Investor’s Commitment Bias and Escalation of Firm’s Investment Decision

    Directory of Open Access Journals (Sweden)

    Anis JARBOUI

    2012-12-01

    Full Text Available This study examines the reasons of perseverance in firm’s investment decision. It shows the possible influence of three closely related features which are: firm’s financial indicators, investor’s risk profile, and investor’s commitment bias, on a firm’s investment decisions escalation. This study aims to provide evidence as to whether investor considers the financial and risk’s perception features (financial strength and risk profile to persevere his initial investment decision while he notes a high level of commitment bias. The proposed model of this paper uses GLM univariate data analyses to examine this relationship. Investor’s risk profile and his commitment bias have been measured by means of a questionnaire comprising several items. As for the selected sample, it has been composed of some 360 Tunisian individual investors. Our results have revealed that investors pay more attention to keep their psychology comfort than their financial comfort. It exposed the importance of the investor’s commitment bias and its risk perception in explaining investment decision escalation. Moreover results shows that there is strong and significant empirical relationship linking the escalatory behavior in investment decision and the interaction effects between the three independent variables. This means that, in practice, investors consider the three factors simultaneously.

  18. Dose escalation study of rhenium-186 hydroxyethylidene diphosphonate in patients with metastatic prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Klerk, J.M.H. de (Dept. of Nuclear Medicine, Univ. Hospital, Utrecht (Netherlands)); Zonnenberg, B.A. (Oncology Section, Dept. of Internal Medicine, Univ. Hospital, Utrecht (Netherlands)); Schip, A.D. van het (Dept. of Nuclear Medicine, Univ. Hospital, Utrecht (Netherlands)); Dijk, A. van (Center for Hospital Pharmacy, Univ. Hospital, Utrecht (Netherlands)); Han, S.H. (Dept. of Nuclear Medicine, Univ. Hospital, Utrecht (Netherlands)); Quirijnen, J.M.S.P. (Dept. of Nuclear Medicine, Univ. Hospital, Utrecht (Netherlands)); Blijham, G.H. (Oncology Section, Dept. of Internal Medicine, Univ. Hospital, Utrecht (Netherlands)); Rijk, P.P. van (Dept. of Nuclear Medicine, Univ. Hospital, Utrecht (Netherlands))

    1994-10-01

    Rhenium-186 hydroxyethylidene diphosphonate ([sup 186]Re-HEDP) has been used for the palliative treatment of metastatic bone pain. A phase 1 dose escalation study was performed using [sup 186]Re-HEDP. Twenty-four patients with hormone-resistant prostate cancer entered the study. Each patient had at least four bone metastases and adequate haematological function. Groups of at least three consecutive patients were treated with doses starting at 1295 MBq and increasing to 3515 MBq (escalated in increments of 555 MBq). Thrombocytopenia proved to be the dose-limiting toxicity, while leucopenia played a minor role. Early death occurred in one patient (10 days after administration) without clear relationship to the [sup 186]Re-HEDP therapy. Transient neurological dysfunction was seen in two cases. Two patients who received 3515 MBq [sup 186]Re-HEDP showed grade 3 toxicity (thrombocytes 25-50 x 10[sup 9]/l), defined as unacceptable toxicity. After treatment alkaline phosphatase levels showed a transient decrease in all patients (mean: 26% [+-] 10% IU/l; range: 11%-44%). Prostate-specific antigen values showed a decline in eight patients, preceded by a temporary increase in three patients. From this study we conclude that the maximally tolerated dose of [sup 186]Re-HEDP is 2960 MBq. A placebo-controlled comparative study on the efficacy of [sup 186]Re-HEDP has been initiated. (orig.)

  19. Control of binder viscosity and hygroscopicity on particle aggregation efficiency

    Science.gov (United States)

    Mueller, Sebastian B.; Kueppers, Ulrich; Ayris, Paul M.; Jacob, Michael; Delmelle, Pierre; Dingwell, Donald B.

    2016-04-01

    In the course of explosive volcanic eruptions, large amounts of ash are released into the atmosphere and may subsequently pose a threat to infrastructure, such as aviation industry. Ash plume forecasting is therefore a crucial tool for volcanic hazard mitigation but may be significantly affected by aggregation, altering the aerodynamic properties of particles. Models struggle with the implementation of aggregation since external conditions promoting aggregation have not been completely understood; in a previous study we have shown the rapid generation of ash aggregates through liquid bonding via the use of fluidization bed technology and further defined humidity and temperature ranges necessary to trigger aggregation. Salt (NaCl) was required for the recovery of stable aggregates, acting as a cementation agent and granting aggregate cohesion. A numerical model was used to explain the physics behind particle aggregation mechanisms and further predicted a dependency of aggregation efficiency on liquid binder viscosity. In this study we proof the effect of viscosity on particle aggregation. HCl and H2SO4 solutions were diluted to various concentrations resulting in viscosities between 1 and 2 mPas. Phonolitic and rhyolitic ash samples as well as soda-lime glass beads (serving as analogue material) were fluidized in the ProCell Lab® of Glatt Ingenieurtechnik GmbH and treated with the acids via a bottom-spray technique. Chemically driven interaction between acid liquids and surfaces of the three used materials led to crystal precipitation. Salt crystals (e.g. NaCl) have been confirmed through scanning electron microscopy (SEM) and leachate analysis. Both volcanic ash samples as well as the glass beads showed a clear dependency of aggregation efficiency on viscosity of the sprayed HCl solution. Spraying H2SO4 provoked a collapse of the fluidized bed and no aggregation has been observed. This is accounted by the high hygroscopicity of H2SO4. Dissolving CaCl2 (known to be

  20. Exciton dynamics in molecular aggregates

    NARCIS (Netherlands)

    Augulis, R.; Pugžlys, A.; Loosdrecht, P.H.M. van; Pugzlys, A

    2006-01-01

    The fundamental aspects of exciton dynamics in double-wall cylindrical aggregates of cyanine dyes are studied by means of frequency resolved femtosecond pump-probe spectroscopy. The collective excitations of the aggregates, resulting from intermolecular dipole-dipole interactions have the characteri

  1. Cartilage tissue engineering using pre-aggregated human articular chondrocytes

    Directory of Open Access Journals (Sweden)

    F Wolf

    2008-12-01

    Full Text Available In this study, we first aimed at determining whether human articular chondrocytes (HAC proliferate in aggregates in the presence of strong chondrocyte mitogens. We then investigated if the aggregated cells have an enhanced chondrogenic capacity as compared to cells cultured in monolayer. HAC from four donors were cultured in tissue culture dishes either untreated or coated with 1% agarose in the presence of TGFb-1, FGF-2 and PDGF-BB. Proliferation and stage of differentiation were assessed by measuring respectively DNA contents and type II collagen mRNA. Expanded cells were induced to differentiate in pellets or in Hyaff®-11 meshes and the formed tissues were analysed biochemically for glycosaminoglycans (GAG and DNA, and histologically by Safranin O staining. The amount of DNA in aggregate cultures increased significantly from day 2 to day 6 (by 3.2-fold, but did not further increase with additional culture time. Expression of type II collagen mRNA was about two orders of magnitude higher in aggregated HAC as compared to monolayer expanded cells. Pellets generated by aggregated HAC were generally more intensely stained for GAG than those generated by monolayer-expanded cells. Scaffolds seeded with aggregates accumulated more GAG (1.3-fold than scaffolds seeded with monolayer expanded HAC. In conclusion, this study showed that HAC culture in aggregates does not support a relevant degree of expansion. However, aggregation of expanded HAC prior to loading into a porous scaffold enhances the quality of the resulting tissues and could thus be introduced as an intermediate culture phase in the manufacture of engineered cartilage grafts.

  2. Dye Aggregation in Ink Jet

    Institute of Scientific and Technical Information of China (English)

    Thomas Paul; Sarfraz Hussain

    2004-01-01

    Dye aggregation has long been recognised as a key factor in performance, and this is no less so in ink jet applications. The aggregation state was shown to be important in many different areas ranging from the use of dyes in photodynamic therapies all the way to colorants for dying of fabrics. Therefore different methods to investigate dye association qualitatively and quantitatively were developed. A simple procedure to study aggregation could be a useful tool to characterise dyes for ink jet printing. It is critically reviewed the methods used to study dye aggregation, and discussed some of the main conclusions. This will be illustrated by examples of ink jet dye aggregation and its study in aqueous and ink systems. The results are used to correlate the solution behaviour of dyes with their print performance.

  3. DRAG ON SUBMICRON NANOPARTICLE AGGREGATES

    Institute of Scientific and Technical Information of China (English)

    F.; Einar; Kruis

    2005-01-01

    A new procedure was developed for estimating the effective collision diameter of an aggregate composed of primary particles of any size. The coagulation coefficient of two oppositely charged particles was measured experimentally and compared with classic Fuchs theory, including a new method to account for particle non-sphericity. A second set of experiments were performed on well-defined nanoparticle aggregates at different stages of sintering, i.e. from the aggregate to the fully sintered stage. Here, electrical mobility was used to characterize the particle drag. The aggregates are being built from two different size-fractionated nanoparticle aerosols, the non-aggregated particles are discarded by an electrofilter and then they are passed through a furnace at concentrations low enough not to induce coagulation.

  4. Optical monitoring of particle aggregates

    Institute of Scientific and Technical Information of China (English)

    John Gregory

    2009-01-01

    Methods for monitoring particle aggregation are briefly reviewed. Most of these techniques are based on some form of light scattering and may be greatly dependent on the optical properties of aggregates, which are not generally known. As fractal aggregates grow larger their density can become very low and this has important practical consequences for light scattering. For instance, the scattering coefficient may be much less than for solid objects, which means that the aggregates can appear much smaller than their actual size by a light transmission method. Also, for low-density objects, a high proportion of the scattered light energy is within a small angle of the incident beam, which may also be relevant for measurements with aggregates.Using the 'turbidity fluctuation' technique as an example, it is shown how the apparent size of hydroxide flocs depends mainly on the included impurity particles, rather than the hydroxide precipitate itself. Results using clay suspensions with hydrolyzing coagulants and under are discussed.

  5. Molecular aggregation of humic substances

    Science.gov (United States)

    Wershaw, R. L.

    1999-01-01

    Humic substances (HS) form molecular aggregates in solution and on mineral surfaces. Elucidation of the mechanism of formation of these aggregates is important for an understanding of the interactions of HS in soils arid natural waters. The HS are formed mainly by enzymatic depolymerization and oxidation of plant biopolymers. These reactions transform the aromatic and lipid plant components into amphiphilic molecules, that is, molecules that consist of separate hydrophobic (nonpolar) and hydrophilic (polar) parts. The nonpolar parts of the molecules are composed of relatively unaltered segments of plant polymers and the polar parts of carboxylic acid groups. These amphiphiles form membrane-like aggregates on mineral surfaces and micelle-like aggregates in solution. The exterior surfaces of these aggregates are hydrophilic, and the interiors constitute separate hydrophobic liquid-like phases.

  6. Orthogonal flexible Rydberg aggregates

    Science.gov (United States)

    Leonhardt, K.; Wüster, S.; Rost, J. M.

    2016-02-01

    We study the link between atomic motion and exciton transport in flexible Rydberg aggregates, assemblies of highly excited light alkali-metal atoms, for which motion due to dipole-dipole interaction becomes relevant. In two one-dimensional atom chains crossing at a right angle adiabatic exciton transport is affected by a conical intersection of excitonic energy surfaces, which induces controllable nonadiabatic effects. A joint exciton-motion pulse that is initially governed by a single energy surface is coherently split into two modes after crossing the intersection. The modes induce strongly different atomic motion, leading to clear signatures of nonadiabatic effects in atomic density profiles. We have shown how this scenario can be exploited as an exciton switch, controlling direction and coherence properties of the joint pulse on the second of the chains [K. Leonhardt et al., Phys. Rev. Lett. 113, 223001 (2014), 10.1103/PhysRevLett.113.223001]. In this article we discuss the underlying complex dynamics in detail, characterize the switch, and derive our isotropic interaction model from a realistic anisotropic one with the addition of a magnetic bias field.

  7. Orthogonal flexible Rydberg aggregates

    CERN Document Server

    Leonhardt, K; Rost, J M

    2015-01-01

    We study the link between atomic motion and exciton transport in flexible Rydberg aggregates, assemblies of highly excited light alkali atoms, for which motion due to dipole-dipole interaction becomes relevant. In two one-dimensional atom chains crossing at a right angle adiabatic exciton transport is affected by a conical intersection of excitonic energy surfaces, which induces controllable non-adiabatic effects. A joint exciton/motion pulse that is initially governed by a single energy surface is coherently split into two modes after crossing the intersection. The modes induce strongly different atomic motion, leading to clear signatures of non-adiabatic effects in atomic density profiles. We have shown how this scenario can be exploited as an exciton switch, controlling direction and coherence properties of the joint pulse on the second of the chains [K.~Leonhardt {\\it et al.}, Phys.~Rev.~Lett. {\\bf 113} 223001 (2014)]. In this article we discuss the underlying complex dynamics in detail, characterise the ...

  8. Perspectives on Preference Aggregation.

    Science.gov (United States)

    Regenwetter, Michel

    2009-07-01

    For centuries, the mathematical aggregation of preferences by groups, organizations, or society itself has received keen interdisciplinary attention. Extensive theoretical work in economics and political science throughout the second half of the 20th century has highlighted the idea that competing notions of rational social choice intrinsically contradict each other. This has led some researchers to consider coherent democratic decision making to be a mathematical impossibility. Recent empirical work in psychology qualifies that view. This nontechnical review sketches a quantitative research paradigm for the behavioral investigation of mathematical social choice rules on real ballots, experimental choices, or attitudinal survey data. The article poses a series of open questions. Some classical work sometimes makes assumptions about voter preferences that are descriptively invalid. Do such technical assumptions lead the theory astray? How can empirical work inform the formulation of meaningful theoretical primitives? Classical "impossibility results" leverage the fact that certain desirable mathematical properties logically cannot hold in all conceivable electorates. Do these properties nonetheless hold true in empirical distributions of preferences? Will future behavioral analyses continue to contradict the expectations of established theory? Under what conditions do competing consensus methods yield identical outcomes and why do they do so?

  9. 自动扶梯金属结构测试探讨%Discussion on Escalator Metal Structural Test

    Institute of Scientific and Technical Information of China (English)

    陈卫红

    2011-01-01

    结合自动扶梯金属结构的挠度测试标准,通过一个测试实例探讨了自动扶梯金属结构的测试过程;利用桁架有限元模型对自动扶梯结构变形量较大的点进行局部挠度计算,计算结果证明符合客户合同的要求。%Combined with the deflection test standard of escalator metal structure, the escalator metal structural test process is discussed through a test case. The local deflection for the larger points of deformation of the escalator structure is calculated by use of the finite element model of truss, The results meet customer contract requirements.

  10. Benzbromarone, Quercetin, and Folic Acid Inhibit Amylin Aggregation

    Directory of Open Access Journals (Sweden)

    Laura C. López

    2016-06-01

    Full Text Available Human Amylin, or islet amyloid polypeptide (hIAPP, is a small hormone secreted by pancreatic β-cells that forms aggregates under insulin deficiency metabolic conditions, and it constitutes a pathological hallmark of type II diabetes mellitus. In type II diabetes patients, amylin is abnormally increased, self-assembled into amyloid aggregates, and ultimately contributes to the apoptotic death of β-cells by mechanisms that are not completely understood. We have screened a library of approved drugs in order to identify inhibitors of amylin aggregation that could be used as tools to investigate the role of amylin aggregation in type II diabetes or as therapeutics in order to reduce β-cell damage. Interestingly, three of the compounds analyzed—benzbromarone, quercetin, and folic acid—are able to slow down amylin fiber formation according to Thioflavin T binding, turbidimetry, and Transmission Electron Microscopy assays. In addition to the in vitro assays, we have tested the effect of these compounds in an amyloid toxicity cell culture model and we have found that one of them, quercetin, has the ability to partly protect cultured pancreatic insulinoma cells from the cytotoxic effect of amylin. Our data suggests that quercetin can contribute to reduce oxidative damage in pancreatic insulinoma β cells by modulating the aggregation propensity of amylin.

  11. Benzbromarone, Quercetin, and Folic Acid Inhibit Amylin Aggregation

    Science.gov (United States)

    López, Laura C.; Varea, Olga; Navarro, Susanna; Carrodeguas, José A.; Sanchez de Groot, Natalia; Ventura, Salvador; Sancho, Javier

    2016-01-01

    Human Amylin, or islet amyloid polypeptide (hIAPP), is a small hormone secreted by pancreatic β-cells that forms aggregates under insulin deficiency metabolic conditions, and it constitutes a pathological hallmark of type II diabetes mellitus. In type II diabetes patients, amylin is abnormally increased, self-assembled into amyloid aggregates, and ultimately contributes to the apoptotic death of β-cells by mechanisms that are not completely understood. We have screened a library of approved drugs in order to identify inhibitors of amylin aggregation that could be used as tools to investigate the role of amylin aggregation in type II diabetes or as therapeutics in order to reduce β-cell damage. Interestingly, three of the compounds analyzed—benzbromarone, quercetin, and folic acid—are able to slow down amylin fiber formation according to Thioflavin T binding, turbidimetry, and Transmission Electron Microscopy assays. In addition to the in vitro assays, we have tested the effect of these compounds in an amyloid toxicity cell culture model and we have found that one of them, quercetin, has the ability to partly protect cultured pancreatic insulinoma cells from the cytotoxic effect of amylin. Our data suggests that quercetin can contribute to reduce oxidative damage in pancreatic insulinoma β cells by modulating the aggregation propensity of amylin. PMID:27322259

  12. Enhanced Shear-induced Platelet Aggregation Due to Low-temperature Storage

    Science.gov (United States)

    2013-07-01

    pathogen inactivation technologies.4,5 In principle, storage of PLTs under refrigeration (4°C), which is standard practice for red blood cells (RBCs), can...by more than 100% (i.e., twofold) compared to freshly isolated PLTs at high shear rates. Effect of cellcell collisions and fluid shear stress on...in aggregating stored PLTs. PLT aggregation under shear is controlled by cellcell collision frequency and the force applied to the cells .26 These

  13. Validation of Treatment Escalation as a Definition of Atopic Eczema Flares

    Science.gov (United States)

    Thomas, Kim S.; Stuart, Beth; O’Leary, Caroline J.; Schmitt, Jochen; Paul, Carle; Williams, Hywel C.; Langan, Sinead

    2015-01-01

    Background Atopic eczema (AE) is a chronic disease with flares and remissions. Long-term control of AE flares has been identified as a core outcome domain for AE trials. However, it is unclear how flares should be defined and measured. Objective To validate two concepts of AE flares based on daily reports of topical medication use: (i) escalation of treatment and (ii) days of topical anti-inflammatory medication use (topical corticosteroids and/or calcineurin inhibitors). Methods Data from two published AE studies (studies A (n=336) and B (n=60)) were analysed separately. Validity and feasibility of flare definitions were assessed using daily global bother (scale 0 to 10) as the reference standard. Intra-class correlations were reported for continuous variables, and odds ratios and area under the receiver operator characteristic (ROC) curve for binary outcome measures. Results Good agreement was found between both AE flare definitions and change in global bother: area under the ROC curve for treatment escalation of 0.70 and 0.73 in studies A and B respectively, and area under the ROC curve of 0.69 for topical anti-inflammatory medication use (Study A only). Significant positive relationships were found between validated severity scales (POEM, SASSAD, TIS) and the duration of AE flares occurring in the previous week – POEM and SASSAD rose by half a point for each unit increase in number of days in flare. Smaller increases were observed on the TIS scale. Completeness of daily diaries was 95% for Study A and 60% for Study B over 16 weeks). Conclusion Both definitions were good proxy indicators of AE flares. We found no evidence that ‘escalation of treatment’ was a better measure of AE flares than ‘use of topical anti-inflammatory medications’. Capturing disease flares in AE trials through daily recording of medication use is feasible and appears to be a good indicator of long-term control. Trial registration Current Controlled Trials ISRCTN71423189 (Study A

  14. Analysis of Islet Cell Antibody of 46 Families with Family Aggregation Diabetes%46个家庭家族聚集性糖尿病胰岛细胞抗体分析及3年观察

    Institute of Scientific and Technical Information of China (English)

    陈飞; 陈月云; 刘瑶; 王安才

    2011-01-01

    Objective To observe the family aggregation of the diabetes especially latent autoimmune diabetes in adults ( LADA) and the predictive effect of islet cell antibody in LADA by testing the islet cell antibody, islet cell function and glycometabolism of 183 siblings without diabetes of 171 diabetics in 46 families. Methods For the families with two or more diabetics in siblings,the islet cell antibodies( GADA ,ICA, IA-2A and IAA) ,islet cell function( fasting and postprandial blood glucose level,C-peptide level) ,body mass index(BMI) and waist hip ratio(WHR) were tested in all probands and their siblings. The positive rate of islet cell antibody and islet cell function in the patients with family aggregation diabetes and their siblings, and the probability of new diabetics after 3 years in these families were observed. Results ①The positive rate of islet cell antibody in the siblings of patients with family aggregation diabetes was higher as compared to that of general populations,and the statistical significance difference was found( P < 0.05 ) ;②The rate of impaired fasting glucose(IFG) and impaired glucose tolerance(IGT) were higher than that of normal people(P <0.05) ;③The risk of LADA in siblings was higher as compared with normal people(P <0.05 ) ;④There was no significant difference in BMI and WHR between the siblings and general type 2 diabetics. Conclusion LADA showed high family aggregation,and the positive rate of islet cell antibody and the incidence of IGT,IFG and diabetes in siblings of patients with LADA was higher than that of general population.%目的 对46个家庭171例糖尿病患者的183例未发糖尿病的同胞进行胰岛细胞抗体,胰岛B细胞功能和糖代谢的检测.以观察糖尿病特别是LADA患者的家族聚集性和胰岛细胞抗体在LADA发病中的预测性.方法 对家族同胞中有2例或2例以上先证糖尿病患者检测其及其他同胞的胰岛细胞抗体(GADA、ICA、IA-2A和IAA).胰岛细胞

  15. The butterfly plant arms-race escalated by gene and genome duplications.

    Science.gov (United States)

    Edger, Patrick P; Heidel-Fischer, Hanna M; Bekaert, Michaël; Rota, Jadranka; Glöckner, Gernot; Platts, Adrian E; Heckel, David G; Der, Joshua P; Wafula, Eric K; Tang, Michelle; Hofberger, Johannes A; Smithson, Ann; Hall, Jocelyn C; Blanchette, Matthieu; Bureau, Thomas E; Wright, Stephen I; dePamphilis, Claude W; Eric Schranz, M; Barker, Michael S; Conant, Gavin C; Wahlberg, Niklas; Vogel, Heiko; Pires, J Chris; Wheat, Christopher W

    2015-07-07

    Coevolutionary interactions are thought to have spurred the evolution of key innovations and driven the diversification of much of life on Earth. However, the genetic and evolutionary basis of the innovations that facilitate such interactions remains poorly understood. We examined the coevolutionary interactions between plants (Brassicales) and butterflies (Pieridae), and uncovered evidence for an escalating evolutionary arms-race. Although gradual changes in trait complexity appear to have been facilitated by allelic turnover, key innovations are associated with gene and genome duplications. Furthermore, we show that the origins of both chemical defenses and of molecular counter adaptations were associated with shifts in diversification rates during the arms-race. These findings provide an important connection between the origins of biodiversity, coevolution, and the role of gene and genome duplications as a substrate for novel traits.

  16. The snowball effect: friendship moderates escalations in depressed affect among avoidant and excluded children.

    Science.gov (United States)

    Bukowski, William M; Laursen, Brett; Hoza, Betsy

    2010-11-01

    A three-wave longitudinal study conducted with preadolescent boys and girls (N = 231 at Time 1 [T1]) was used to assess the hypotheses that aspects of social withdrawal would be predictors of a "snowball" cascade of depressed affect, and that friendship experiences would moderate these effects. Consistent with these hypotheses, multilevel modeling showed that measures of avoidance and exclusion at T1 were associated with concurrent levels of depressed affect and were antecedent to escalating trajectories of depressed affect over time. These accelerating growth curves fit a snowball cascade model. The analyses also showed the protective effects of friendship. Specifically, the snowball effect was limited to avoidant and excluded children who were friendless. Depressed affect did not increase among avoidant and excluded children who were friended.

  17. Escalation, timing and severity of insurgent and terrorist events: Toward a unified theory of future threats

    CERN Document Server

    Johnson, Neil F

    2011-01-01

    I present a unified discussion of several recently published results concerning the escalation, timing and severity of violent events in human conflicts and global terrorism, and set them in the wider context of real-world and cyber-based collective violence and illicit activity. I point out how the borders distinguishing between such activities are becoming increasingly blurred in practice -- from insurgency, terrorism, criminal gangs and cyberwars, through to the 2011 Arab Spring uprisings and London riots. I review the robust empirical patterns that have been found, and summarize a minimal mechanistic model which can explain these patterns. I also explain why this mechanistic approach, which is inspired by non-equilibrium statistical physics, fits naturally within the framework of recent ideas within the social science literature concerning analytical sociology. In passing, I flag the fundamental flaws in each of the recent critiques which have surfaced concerning the robustness of these results and the re...

  18. Escalation with Overdose Control Using Ordinal Toxicity Grades for Cancer Phase I Clinical Trials

    Directory of Open Access Journals (Sweden)

    Mourad Tighiouart

    2012-01-01

    Full Text Available We extend a Bayesian adaptive phase I clinical trial design known as escalation with overdose control (EWOC by introducing an intermediate grade 2 toxicity when assessing dose-limiting toxicity (DLT. Under the proportional odds model assumption of dose-toxicity relationship, we prove that in the absence of DLT, the dose allocated to the next patient given that the previously treated patient had a maximum of grade 2 toxicity is lower than the dose given to the next patient had the previously treated patient exhibited a grade 0 or 1 toxicity at the most. Further, we prove that the coherence properties of EWOC are preserved. Simulation results show that the safety of the trial is not compromised and the efficiency of the estimate of the maximum tolerated dose (MTD is maintained relative to EWOC treating DLT as a binary outcome and that fewer patients are overdosed using this design when the true MTD is close to the minimum dose.

  19. Dose-Escalated Intensity-Modulated Radiotherapy Is Feasible and May Improve Locoregional Control and Laryngeal Preservation in Laryngo-Hypopharyngeal Cancers

    Energy Technology Data Exchange (ETDEWEB)

    Miah, Aisha B.; Bhide, Shreerang A.; Guerrero-Urbano, M. Teresa [Head and Neck Unit, The Royal Marsden National Health Service (NHS) Foundation Trust, London (United Kingdom); Institute of Cancer Research, London (United Kingdom); Clark, Catharine; Bidmead, A. Margaret [Institute of Cancer Research, London (United Kingdom); Department of Physics, The Royal Marsden NHS Foundation Trust, London (United Kingdom); St Rose, Suzanne; Barbachano, Yolanda; A' Hern, Roger [Department of Statistics, The Royal Marsden NHS Foundation Trust, London (United Kingdom); Tanay, Mary; Hickey, Jennifer; Nicol, Robyn; Newbold, Kate L. [Head and Neck Unit, The Royal Marsden National Health Service (NHS) Foundation Trust, London (United Kingdom); Harrington, Kevin J. [Head and Neck Unit, The Royal Marsden National Health Service (NHS) Foundation Trust, London (United Kingdom); Institute of Cancer Research, London (United Kingdom); Nutting, Christopher M., E-mail: chris.nutting@rmh.nhs.uk [Head and Neck Unit, The Royal Marsden National Health Service (NHS) Foundation Trust, London (United Kingdom); Institute of Cancer Research, London (United Kingdom)

    2012-02-01

    Purpose: To determine the safety and outcomes of induction chemotherapy followed by dose-escalated intensity-modulated radiotherapy (IMRT) with concomitant chemotherapy in locally advanced squamous cell cancer of the larynx and hypopharynx (LA-SCCL/H). Methods and Materials: A sequential cohort Phase I/II trial design was used to evaluate moderate acceleration and dose escalation. Patients with LA-SCCL/H received IMRT at two dose levels (DL): DL1, 63 Gy/28 fractions (Fx) to planning target volume 1 (PTV1) and 51.8 Gy/28 Fx to PTV2; DL2, 67.2 Gy/28 Fx and 56 Gy/28 Fx to PTV1 and PTV2, respectively. Patients received induction cisplatin/5-fluorouracil and concomitant cisplatin. Acute and late toxicities and tumor control rates were recorded. Results: Between September 2002 and January 2008, 60 patients (29 DL1, 31 DL2) with Stage III (41% DL1, 52% DL2) and Stage IV (52% DL1, 48% DL2) disease were recruited. Median (range) follow-up for DL1 was 51.2 (12.1-77.3) months and for DL2 was 36.2 (4.2-63.3) months. Acute Grade 3 (G3) dysphagia was higher in DL2 (87% DL2 vs. 59% DL1), but other toxicities were equivalent. One patient in DL1 required dilatation of a pharyngeal stricture (G3 dysphagia). In DL2, 2 patients developed benign pharyngeal strictures at 1 year. One underwent a laryngo-pharyngectomy and the other a dilatation. No other G3/G4 toxicities were reported. Overall complete response was 79% (DL1) and 84% (DL2). Two-year locoregional progression-free survival rates were 64.2% (95% confidence interval, 43.5-78.9%) in DL1 and 78.4% (58.1-89.7%) in DL2. Two-year laryngeal preservation rates were 88.7% (68.5-96.3%) in DL1 and 96.4% (77.7-99.5%) in DL2. Conclusions: At a mean follow-up of 36 months, dose-escalated chemotherapy-IMRT at DL2 has so far been safe to deliver. In this study, DL2 delivered high rates of locoregional control, progression-free survival, and organ preservation and has been selected as the experimental arm in a Cancer Research UK Phase III

  20. Methylphenidate as a reinforcer for rats: contingent delivery and intake escalation.

    Science.gov (United States)

    Marusich, Julie A; Beckmann, Joshua S; Gipson, Cassandra D; Bardo, Michael T

    2010-06-01

    Methylphenidate (MPH) is one of the most widely prescribed drugs for treating attention-deficit hyperactivity disorder. Previous research suggested that MPH is a reinforcer for rats, but not all of the manipulations to show that lever pressing is controlled by the contingency to obtain MPH have been examined. In Experiment 1, responding for MPH on a progressive ratio (PR) schedule was assessed. Rats self-administered varying doses of MPH (0.056-1.0 mg/kg/infusion) on a PR schedule of reinforcement, and self-administered more MPH than saline, with maximal responding occurring at a unit dose of 0.56 mg/kg/infusion. Experiment 2 examined if there were differences in responding between contingent and noncontingent MPH (0.56 mg/kg/infusion) on a fixed ratio schedule of reinforcement. Results showed that rats responded for contingent MPH, and that responding was not maintained when MPH was delivered noncontingently. Experiment 3 examined self-administration of MPH (0.1 or 0.3 mg/kg/infusion) during long access (6 hr) compared to short access sessions (1 hr). Results showed that rats given long access to MPH showed an escalation of intake across sessions, with this escalation being more pronounced at the lower unit dose (0.1 mg/kg/infusion); in contrast, rats given short access to MPH did not show an increase in MPH self-administration across sessions at either MPH dose tested. Taken together, these results indicate that MPH is an effective intravenous reinforcer for rats and that, similar to other stimulants such as cocaine, amphetamine and methamphetamine, MPH is subject to abuse as reflected by dysregulated intake across repeated long access sessions.

  1. Radiation Therapy Dose Escalation for Glioblastoma Multiforme in the Era of Temozolomide

    Energy Technology Data Exchange (ETDEWEB)

    Badiyan, Shahed N.; Markovina, Stephanie; Simpson, Joseph R.; Robinson, Clifford G.; DeWees, Todd [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri (United States); Tran, David D.; Linette, Gerry [Division of Medical Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri (United States); Jalalizadeh, Rohan [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri (United States); Dacey, Ralph; Rich, Keith M.; Chicoine, Michael R.; Dowling, Joshua L.; Leuthardt, Eric C.; Zipfel, Gregory J.; Kim, Albert H. [Department of Neurosurgery, Washington University School of Medicine, St. Louis, Missouri (United States); Huang, Jiayi, E-mail: jhuang@radonc.wustl.edu [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri (United States)

    2014-11-15

    Purpose: To review clinical outcomes of moderate dose escalation using high-dose radiation therapy (HDRT) in the setting of concurrent temozolomide (TMZ) in patients with newly diagnosed glioblastoma multiforme (GBM), compared with standard-dose radiation therapy (SDRT). Methods and Materials: Adult patients aged <70 years with biopsy-proven GBM were treated with SDRT (60 Gy at 2 Gy per fraction) or with HDRT (>60 Gy) and TMZ from 2000 to 2012. Biological equivalent dose at 2-Gy fractions was calculated for the HDRT assuming an α/β ratio of 5.6 for GBM. Results: Eighty-one patients received SDRT, and 128 patients received HDRT with a median (range) biological equivalent dose at 2-Gy fractions of 64 Gy (61-76 Gy). Overall median follow-up time was 1.10 years, and for living patients it was 2.97 years. Actuarial 5-year overall survival (OS) and progression-free survival (PFS) rates for patients that received HDRT versus SDRT were 12.4% versus 13.2% (P=.71), and 5.6% versus 4.1% (P=.54), respectively. Age (P=.001) and gross total/near-total resection (GTR/NTR) (P=.001) were significantly associated with PFS on multivariate analysis. Younger age (P<.0001), GTR/NTR (P<.0001), and Karnofsky performance status ≥80 (P=.001) were associated with improved OS. On subset analyses, HDRT failed to improve PFS or OS for those aged <50 years or those who had GTR/NTR. Conclusion: Moderate radiation therapy dose escalation above 60 Gy with concurrent TMZ does not seem to improve clinical outcomes for patients with GBM.

  2. Capecitabine based postoperative accelerated chemoradiation of pancreatic carcinoma. A dose-escalation study

    Energy Technology Data Exchange (ETDEWEB)

    Morganti, Alessio G.; Picardi, Vincenzo; Ippolito, Edy; Massaccesi, Mariangela; Macchia, Gabriella; Deodato, Francesco (Radiotherapy Unit, Dept. of Oncology, ' John Paul II' Center for High Technology Research and Education in Biomedical Sciences, Catholic Univ., Campobasso (Italy)), E-mail: gmacchia@rm.unicatt.it; Caravatta, Luciana; Tambaro, Rosa; Mignogna, Samantha (Palliative Therapies Unit, Dept. of Oncology, ' John Paul II' Center for High Technology Research and Education in Biomedical Sciences, Catholic Univ., Campobasso (Italy)); Cellini, Numa; Valentini, Vincenzo; Mattiucci, Gian Carlo (Dept. of Radiotherapy, Policlinico Universitario ' A. Gemelli' , Catholic Univ., Rome (Italy)); Di Lullo, Liberato (Dept. of Oncology, ' F. Veneziale' General Hospital, Isernia (Italy)); Giglio, Gianfranco (Dept. of Oncology, ' A. Cardarelli' General Hospital Campobasso (Italy)); Caprino, Paola; Sofo, Luigi (Surgery Unit, Dept. of Oncology, ' John Paul II' Center for High Technology Research and Education in Biomedical Sciences, Catholic Univ., Campobasso (Italy)); Ingrosso, Marcello (Endoscopy Unit, Dept. of Oncology, ' John Paul II' Center for High Technology Research and Education in Biomedical Sciences, Catholic Univ., Campobasso (Italy))

    2010-05-15

    The objective of this study was to evaluate the safety of escalating up to 55 Gy within five weeks, the dose of external beam radiotherapy to the previous tumor site concurrently with a fixed daily dose of capecitabine, in patients with resected pancreatic cancer. Material and methods. Patients with resected pancreatic carcinoma were eligible for this study. Capecitabine was administered at a daily dose of 1600 mg/m2. Regional lymph nodes received a total radiation dose of 45 Gy with 1.8 Gy per fractions. The starting radiation dose to the tumor bed was 50.0 Gy (2.0 Gy/fraction, 25 fractions). Escalation was achieved up to a total dose of 55.0 Gy by increasing the fraction size by 0.2 Gy (2.2 Gy/fraction), while keeping the duration of radiotherapy to five weeks (25 fractions). A concomitant boost technique was used. Dose limiting toxicity (DLT) was defined as any grade>3 hematologic toxicity, grade>2 liver, renal, neurologic, gastrointestinal, or skin toxicity, by RTOG criteria, or any toxicity producing prolonged (> 10 days) radiotherapy interruption. Results and discussion. Twelve patients entered the study (median age: 64 years). In the first cohort (six patients), no patient experienced DLT. Similarly in the second cohort, no DLT occurred. All 12 patients completed the planned regimen of therapy. Nine patients experienced grade 1-2 nausea and/or vomiting. Grade 2 hematological toxicity occurred in four patients. The results of our study indicate that a total radiation dose up to 55.0 Gy/5 weeks can be safely administered to the tumor bed, concurrently with capecitabine (1600 mg/m2) in patients with resected pancreatic carcinoma.

  3. The Role of Age on Dose Limiting Toxicities (DLTs) in Phase I Dose-escalation Trials

    Science.gov (United States)

    Schwandt, A; Harris, P. J.; Hunsberger, S.; Deleporte, A.; Smith, G. L.; Vulih, D.; Anderson, B. D.; Ivy, S. P.

    2016-01-01

    Purpose Elderly oncology patients are not enrolled in early phase trials in proportion to the numbers of geriatric patients with cancer. There may be concern that elderly patients will not tolerate investigational agents as well as younger patients resulting in a disproportionate number of dose-limiting toxicities (DLTs). Recent single-institution studies provide conflicting data on the relationship between age and DLT. Experimental Design We retrospectively reviewed data about patients treated on single-agent, dose-escalation, phase I clinical trials sponsored by the Cancer Therapy Evaluation Program (CTEP) of the National Cancer Institute. Patients’ dose levels were described as percentage of maximum tolerated dose (%MTD), the highest dose level at which <33% of patients had a DLT, or recommended phase II dose (RP2D). Mixed-effect logistic regression models were used to analyze relationships between the probability of a DLT and age and other explanatory variables. Results Increasing dose, increasing age, and worsening performance status (PS) were significantly related to an increased probability of a DLT in this model (p<0.05). There was no association between dose level administered and age (p=0.57). Conclusions This analysis of phase I dose-escalation trials involving over 500 patients older than 70 years of age, is the largest reported. As age and dose level increased and PS worsened, the probability of a DLT increased. While increasing age was associated with occurrence of DLT, this risk remained within accepted thresholds of risk for phase I trials. There was no evidence of age bias on enrollment of patients on low or high dose levels. PMID:25028396

  4. Caspofungin dose escalation for invasive candidiasis due to resistant Candida albicans.

    Science.gov (United States)

    Wiederhold, Nathan P; Najvar, Laura K; Bocanegra, Rosie A; Kirkpatrick, William R; Patterson, Thomas F

    2011-07-01

    Previous in vivo studies have reported caspofungin dose escalation to be effective against Candida glabrata with reduced susceptibility. We hypothesized that higher doses of caspofungin would be effective against invasive candidiasis caused by the more virulent species Candida albicans, including isolates resistant to this echinocandin. Immunocompetent mice were inoculated with one of three C. albicans isolates, including one susceptible and two resistant isolates with different FKS1 hot spot 1 point mutations. Mice received daily caspofungin treatment for 7 days and were then followed off therapy for 2 weeks to assess survival. Kidney tissue and blood were collected, and fungal burden and serum (1 → 3)-β-D-glucan were measured. Significant differences in virulence were observed among the three C. albicans isolates, which translated into differences in responses to caspofungin. The most virulent of the resistant isolates studied (isolate 43001; Fks1p F641S) did not respond to caspofungin doses of up to 10 mg/kg of body weight, as there were no differences in survival (survival range, 0 to 12% with treatment), tissue burden, or (1 → 3)-β-D-glucan concentration compared to those for untreated controls. Higher doses of caspofungin did improve survival against the second resistant isolate (53264; Fks1p S645P) that demonstrated reduced virulence (5 and 10 mg/kg; 80% survival). In contrast, caspofungin doses as low as 1 mg/kg improved survival (85 to 95%) and reduced tissue burden and (1 → 3)-β-D-glucan concentration against the susceptible isolate (ATCC 90028). These data suggest that caspofungin dose escalation for invasive candidiasis may not be consistently effective against resistant C. albicans isolates, and this may be associated with the virulence of the strain.

  5. Dependability in Aggregation by Averaging

    CERN Document Server

    Jesus, Paulo; Almeida, Paulo Sérgio

    2010-01-01

    Aggregation is an important building block of modern distributed applications, allowing the determination of meaningful properties (e.g. network size, total storage capacity, average load, majorities, etc.) that are used to direct the execution of the system. However, the majority of the existing aggregation algorithms exhibit relevant dependability issues, when prospecting their use in real application environments. In this paper, we reveal some dependability issues of aggregation algorithms based on iterative averaging techniques, giving some directions to solve them. This class of algorithms is considered robust (when compared to common tree-based approaches), being independent from the used routing topology and providing an aggregation result at all nodes. However, their robustness is strongly challenged and their correctness often compromised, when changing the assumptions of their working environment to more realistic ones. The correctness of this class of algorithms relies on the maintenance of a funda...

  6. Aggregating and Disaggregating Flexibility Objects

    DEFF Research Database (Denmark)

    Siksnys, Laurynas; Valsomatzis, Emmanouil; Hose, Katja

    2015-01-01

    In many scientific and commercial domains we encounter flexibility objects, i.e., objects with explicit flexibilities in a time and an amount dimension (e.g., energy or product amount). Applications of flexibility objects require novel and efficient techniques capable of handling large amounts...... energy data management and discuss strategies for aggregation and disaggregation of flex-objects while retaining flexibility. This paper further extends these approaches beyond flex-objects originating from energy consumption by additionally considering flex-objects originating from energy production...... and aiming at energy balancing during aggregation. In more detail, this paper considers the complete life cycle of flex-objects: aggregation, disaggregation, associated requirements, efficient incremental computation, and balance aggregation techniques. Extensive experiments based on real-world data from...

  7. Lactose-Functionalized Dendrimers Arbitrate the Interaction of Galectin-3/MUC1 Mediated Cancer Cellular Aggregation

    Science.gov (United States)

    Michel, Anna K.; Nangia-Makker, Pratima; Raz, Avraham

    2015-01-01

    By using lactose-functionalized poly(amidoamine) dendrimers as a tunable multivalent platform, we studied cancer cell aggregation in three different cell lines (A549, DU-145, and HT-1080) with galectin-3. We found that small lactose-functionalized G(2)-dendrimer 1 inhibited galectin-3-induced aggregation of the cancer cells. In contrast, dendrimer 4 (a larger, generation 6 dendrimer with 100 carbohydrate end groups) caused cancer cells to aggregate through a galectin-3 pathway. This study indicates that inhibition of cellular aggregation occurred because 1 provided competitive binding sites for galectin-3 (compared to its putative cancer cell ligand, TF-antigen on MUC1). Dendrimer 4, in contrast, provided an excess of ligands for galectin-3 binding; this caused crosslinking and aggregation of cells to be increased. PMID:25138772

  8. Words of Violence: “Fear Speech,” or How Violent Conflict Escalation Relates to the Freedom of Expression

    NARCIS (Netherlands)

    Buyse, Antoine

    2014-01-01

    The limits of the freedom of expression are a perennial discussion in human rights discourse. This article focuses on identifying yardsticks to establish the boundaries of freedom of expression in cases where violence is a risk. It does so by using insights from the social sciences on the escalation

  9. A Phase I Dose-Escalation Study of Antibody BI-505 in Relapsed/Refractory Multiple Myeloma

    DEFF Research Database (Denmark)

    Hansson, Markus; Gimsing, Peter; Badros, Ashraf;

    2015-01-01

    , at escalating doses from 0.0004 to 20 mg/kg, with extension of therapy until disease progression for responding or stable patients receiving 0.09 mg/kg or higher doses. RESULTS: A total of 35 patients were enrolled. The most common adverse events were fatigue, pyrexia, headache, and nausea. Adverse events were...

  10. An Investigation of the Relationships between Goals and Software Project Escalation: Insights from Goal Setting and Goal Orientation Theories

    Science.gov (United States)

    Lee, Jong Seok

    2013-01-01

    Escalation of commitment is manifested as a behavior in which an individual resists withdrawing from a failing course of action despite negative feedback, and it is an enduring problem that occurs in a variety of situations, including R&D investment decisions and software project overruns. To date, a variety of theoretical explanations have…

  11. Escalation of Commitment to an Ineffective Course of Action: The Effect of Feedback Having Negative Implications for Self-Identity.

    Science.gov (United States)

    Brockner, Joel; And Others

    1986-01-01

    Examines entrapment, the process by which organizational decision makers escalate commitment to an ineffective course of action to justify allocation of previous resources. Two laboratory experiments exploring individuals' perceptions of entrapment and its effect on their self identity are described. Also discusses practical theoretical…

  12. Localization of protein aggregation in Escherichia coli is governed by diffusion and nucleoid macromolecular crowding effect.

    Science.gov (United States)

    Coquel, Anne-Sophie; Jacob, Jean-Pascal; Primet, Mael; Demarez, Alice; Dimiccoli, Mariella; Julou, Thomas; Moisan, Lionel; Lindner, Ariel B; Berry, Hugues

    2013-04-01

    Aggregates of misfolded proteins are a hallmark of many age-related diseases. Recently, they have been linked to aging of Escherichia coli (E. coli) where protein aggregates accumulate at the old pole region of the aging bacterium. Because of the potential of E. coli as a model organism, elucidating aging and protein aggregation in this bacterium may pave the way to significant advances in our global understanding of aging. A first obstacle along this path is to decipher the mechanisms by which protein aggregates are targeted to specific intercellular locations. Here, using an integrated approach based on individual-based modeling, time-lapse fluorescence microscopy and automated image analysis, we show that the movement of aging-related protein aggregates in E. coli is purely diffusive (Brownian). Using single-particle tracking of protein aggregates in live E. coli cells, we estimated the average size and diffusion constant of the aggregates. Our results provide evidence that the aggregates passively diffuse within the cell, with diffusion constants that depend on their size in agreement with the Stokes-Einstein law. However, the aggregate displacements along the cell long axis are confined to a region that roughly corresponds to the nucleoid-free space in the cell pole, thus confirming the importance of increased macromolecular crowding in the nucleoids. We thus used 3D individual-based modeling to show that these three ingredients (diffusion, aggregation and diffusion hindrance in the nucleoids) are sufficient and necessary to reproduce the available experimental data on aggregate localization in the cells. Taken together, our results strongly support the hypothesis that the localization of aging-related protein aggregates in the poles of E. coli results from the coupling of passive diffusion-aggregation with spatially non-homogeneous macromolecular crowding. They further support the importance of "soft" intracellular structuring (based on macromolecular

  13. Localization of protein aggregation in Escherichia coli is governed by diffusion and nucleoid macromolecular crowding effect.

    Directory of Open Access Journals (Sweden)

    Anne-Sophie Coquel

    2013-04-01

    Full Text Available Aggregates of misfolded proteins are a hallmark of many age-related diseases. Recently, they have been linked to aging of Escherichia coli (E. coli where protein aggregates accumulate at the old pole region of the aging bacterium. Because of the potential of E. coli as a model organism, elucidating aging and protein aggregation in this bacterium may pave the way to significant advances in our global understanding of aging. A first obstacle along this path is to decipher the mechanisms by which protein aggregates are targeted to specific intercellular locations. Here, using an integrated approach based on individual-based modeling, time-lapse fluorescence microscopy and automated image analysis, we show that the movement of aging-related protein aggregates in E. coli is purely diffusive (Brownian. Using single-particle tracking of protein aggregates in live E. coli cells, we estimated the average size and diffusion constant of the aggregates. Our results provide evidence that the aggregates passively diffuse within the cell, with diffusion constants that depend on their size in agreement with the Stokes-Einstein law. However, the aggregate displacements along the cell long axis are confined to a region that roughly corresponds to the nucleoid-free space in the cell pole, thus confirming the importance of increased macromolecular crowding in the nucleoids. We thus used 3D individual-based modeling to show that these three ingredients (diffusion, aggregation and diffusion hindrance in the nucleoids are sufficient and necessary to reproduce the available experimental data on aggregate localization in the cells. Taken together, our results strongly support the hypothesis that the localization of aging-related protein aggregates in the poles of E. coli results from the coupling of passive diffusion-aggregation with spatially non-homogeneous macromolecular crowding. They further support the importance of "soft" intracellular structuring (based on

  14. Pathophysiological importance of aggregated damaged proteins.

    Science.gov (United States)

    Höhn, Annika; Jung, Tobias; Grune, Tilman

    2014-06-01

    Reactive oxygen species (ROS) are formed continuously in the organism even under physiological conditions. If the level of ROS in cells exceeds the cellular defense capacity, components such as RNA/DNA, lipids, and proteins are damaged and modified, thus affecting the functionality of organelles as well. Proteins are especially prominent targets of various modifications such as oxidation, glycation, or conjugation with products of lipid peroxidation, leading to the alteration of their biological function, nonspecific interactions, and the production of high-molecular-weight protein aggregates. To ensure the maintenance of cellular functions, two proteolytic systems are responsible for the removal of oxidized and modified proteins, especially the proteasome and organelles, mainly the autophagy-lysosomal systems. Furthermore, increased protein oxidation and oxidation-dependent impairment of proteolytic systems lead to an accumulation of oxidized proteins and finally to the formation of nondegradable protein aggregates. Accordingly, the cellular homeostasis cannot be maintained and the cellular metabolism is negatively affected. Here we address the current knowledge of protein aggregation during oxidative stress, aging, and disease.

  15. Comparative analysis of super-shedder strains of Escherichia coli O157:H7 reveals distinctive genomic features and a strongly aggregative adherent phenotype on bovine rectoanal junction squamous epithelial cells.

    Directory of Open Access Journals (Sweden)

    Rebecca Cote

    Full Text Available Shiga toxin-producing Escherichia coli O157:H7 (O157 are significant foodborne pathogens and pose a serious threat to public health worldwide. The major reservoirs of O157 are asymptomatic cattle which harbor the organism in the terminal recto-anal junction (RAJ. Some colonized animals, referred to as "super-shedders" (SS, are known to shed O157 in exceptionally large numbers (>104 CFU/g of feces. Recent studies suggest that SS cattle play a major role in the prevalence and transmission of O157, but little is known about the molecular mechanisms associated with super-shedding. Whole genome sequence analysis of an SS O157 strain (SS17 revealed a genome of 5,523,849 bp chromosome with 5,430 open reading frames and two plasmids, pO157 and pSS17, of 94,645 bp and 37,446 bp, respectively. Comparative analyses showed that SS17 is clustered with spinach-associated O157 outbreak strains, and belongs to the lineage I/II, clade 8, D group, and genotype 1, a subgroup of O157 with predicted hyper-virulence. A large number of non-synonymous SNPs and other polymorphisms were identified in SS17 as compared with other O157 strains (EC4115, EDL933, Sakai, TW14359, including in key adherence- and virulence-related loci. Phenotypic analyses revealed a distinctive and strongly adherent aggregative phenotype of SS17 on bovine RAJ stratified squamous epithelial (RSE cells that was conserved amongst other SS isolates. Molecular genetic and functional analyses of defined mutants of SS17 suggested that the strongly adherent aggregative phenotype amongst SS isolates is LEE-independent, and likely results from a novel mechanism. Taken together, our study provides a rational framework for investigating the molecular mechanisms associated with SS, and strong evidence that SS O157 isolates have distinctive features and use a LEE-independent mechanism for hyper-adherence to bovine rectal epithelial cells.

  16. Ash Aggregates in Proximal Settings

    Science.gov (United States)

    Porritt, L. A.; Russell, K.

    2012-12-01

    Ash aggregates are thought to have formed within and been deposited by the eruption column and plume and dilute density currents and their associated ash clouds. Moist, turbulent ash clouds are considered critical to ash aggregate formation by facilitating both collision and adhesion of particles. Consequently, they are most commonly found in distal deposits. Proximal deposits containing ash aggregates are less commonly observed but do occur. Here we describe two occurrences of vent proximal ash aggregate-rich deposits; the first within a kimberlite pipe where coated ash pellets and accretionary lapilli are found within the intra-vent sequence; and the second in a glaciovolcanic setting where cored pellets (armoured lapilli) occur within Diamond Mine, Canada, are the residual deposits within the conduit and vent of the volcano and are characterised by an abundance of ash aggregates. Coated ash pellets are dominant but are followed in abundance by ash pellets, accretionary lapilli and rare cored pellets. The coated ash pellets typically range from 1 - 5 mm in diameter and have core to rim ratios of approximately 10:1. The formation and preservation of these aggregates elucidates the style and nature of the explosive phase of kimberlite eruption at A418 (and other pipes?). First, these pyroclasts dictate the intensity of the kimberlite eruption; it must be energetic enough to cause intense fragmentation of the kimberlite to produce a substantial volume of very fine ash (sustained plume attended by concomitant production of pyroclastic density currents. The size and internal structure of the armoured lapilli provide constraints on the nature of the initial explosive phase of eruption at Kima'Kho. Their proximity to the vent also indicates rapid aggregation within the eruption plume. Within both sequences rapid aggregation of ash particles occurred in proximity to the vent. However, the conditions were substantially different leading to the production of armoured

  17. Multivalent scaffolds induce galectin-3 aggregation into nanoparticles

    Directory of Open Access Journals (Sweden)

    Candace K. Goodman

    2014-07-01

    Full Text Available Galectin-3 meditates cell surface glycoprotein clustering, cross linking, and lattice formation. In cancer biology, galectin-3 has been reported to play a role in aggregation processes that lead to tumor embolization and survival. Here, we show that lactose-functionalized dendrimers interact with galectin-3 in a multivalent fashion to form aggregates. The glycodendrimer–galectin aggregates were characterized by dynamic light scattering and fluorescence microscopy methodologies and were found to be discrete particles that increased in size as the dendrimer generation was increased. These results show that nucleated aggregation of galectin-3 can be regulated by the nucleating polymer and provide insights that improve the general understanding of the binding and function of sugar-binding proteins.

  18. Multivalent scaffolds induce galectin-3 aggregation into nanoparticles

    Science.gov (United States)

    Goodman, Candace K; Wolfenden, Mark L; Nangia-Makker, Pratima; Michel, Anna K; Raz, Avraham

    2014-01-01

    Summary Galectin-3 meditates cell surface glycoprotein clustering, cross linking, and lattice formation. In cancer biology, galectin-3 has been reported to play a role in aggregation processes that lead to tumor embolization and survival. Here, we show that lactose-functionalized dendrimers interact with galectin-3 in a multivalent fashion to form aggregates. The glycodendrimer–galectin aggregates were characterized by dynamic light scattering and fluorescence microscopy methodologies and were found to be discrete particles that increased in size as the dendrimer generation was increased. These results show that nucleated aggregation of galectin-3 can be regulated by the nucleating polymer and provide insights that improve the general understanding of the binding and function of sugar-binding proteins. PMID:25161713

  19. An Aß concatemer with altered aggregation propensities

    DEFF Research Database (Denmark)

    Giehm, L; Dal Degan, F; Fraser, P;

    2010-01-01

    We present an analysis of the conformational and aggregative properties of an A beta concatemer (Con-Alz) of interest for vaccine development against Alzheimer's disease. Con-Alz consists of 3 copies of the 43 residues of the A beta peptide separated by the P2 and P30 T-cell epitopes from...... stage in the fibrillation process. Physically linking multiple copies of the A beta-peptide may thus sterically restrict Con-Alz against forming cytotoxic oligomers, forcing it instead to adopt a less well-organized assembly of intermeshed polypeptide chains. (C) 2010 Elsevier B.V. All rights reserved....

  20. Fractal Aggregates in Tennis Ball Systems

    Science.gov (United States)

    Sabin, J.; Bandin, M.; Prieto, G.; Sarmiento, F.

    2009-01-01

    We present a new practical exercise to explain the mechanisms of aggregation of some colloids which are otherwise not easy to understand. We have used tennis balls to simulate, in a visual way, the aggregation of colloids under reaction-limited colloid aggregation (RLCA) and diffusion-limited colloid aggregation (DLCA) regimes. We have used the…

  1. A Functional Reference Architecture for Aggregators

    DEFF Research Database (Denmark)

    Bondy, Daniel Esteban Morales; Heussen, Kai; Gehrke, Oliver;

    2015-01-01

    Aggregators are considered to be a key enabling technology for harvesting power system services from distributed energy resources (DER). As a precondition for more widespread use of aggregators in power systems, methods for comparing and validating aggregator designs must be established. This paper...... proposes a functional reference architecture for aggregators to address this requirement....

  2. Hierarchical organization in aggregates of protein molecules

    DEFF Research Database (Denmark)

    Bohr, Henrik; Kyhle, Anders; Sørensen, Alexis Hammer

    1997-01-01

    The aggregation of proteins into small clusters is studied by atomic force and electron microscopy. Scaling laws and fractal behaviour in the growth of the aggregates and in the correlation between aggregates is seen. A phase diagram of the aggregation process where the protonic concentration...

  3. Genetic effects on variation in red-blood-cell folate in adults: Implications for the familial aggregation of neural tube defects

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, L.E. [Children`s Hospital of Philadelphia, PA (United States); Duffy, P.; Bellingham, G. [Prince Charles Hospital, Brisbane (Australia)] [and others

    1997-02-01

    Recent studies have implicated folic acid as an important determinant of normal human growth, development, and function. Insufficient folate levels appear to be a risk factor for neural tube defects (NTD), as well as for several chronic diseases of adulthood. However, relatively little is known about the factors that influence folate status in the general population. To estimate the relative contribution of genetic and nongenetic factors to variation in folate, we have evaluated red blood cell (RBC) folate levels in 440 pairs of MZ twins and in 331 pairs of DZ twins. The data were best described by a model in which 46% of the variance in RBC folate was attributable to additive genetic effects, 16% of the variance was due to measured phenotypic covariates, and 38% of the variance was due to random environmental effects. Moreover, the correlations for RBC folate in MZ co-twins (r = .46) and in repeat measures from the same individual (r = .51) were very similar, indicating that virtually all repeatable variation in RBC folate is attributable to genetic factors. On the basis of these results, it would seem reasonable to initiate a search for the specific genes that influence RBC folate levels in the general population. Such genes ultimately may be used to identify individuals at increased risk for NTD and other folate-related diseases. 23 refs., 1 tab.

  4. An exact approach for aggregated formulations

    DEFF Research Database (Denmark)

    Gamst, Mette; Spoorendonk, Simon; Røpke, Stefan

    optimality cannot be guaranteed by branching on aggregated variables. We present a generic exact solution method to remedy the drawbacks of aggregation. It combines the original and aggregated formulations and applies Benders' decomposition. We apply the method to the Split Delivery Vehicle Routing Problem.......Aggregating formulations is a powerful approach for problems to take on tractable forms. Aggregation may lead to loss of information, i.e. the aggregated formulation may be an approximation of the original problem. In branch-and-bound context, aggregation can also complicate branching, e.g. when...

  5. Aggregation and sedimentation processes during a spring phytoplankton bloom: A field experiment to test coagulation theory

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Lundsgaard, Claus; Olesen, Michael;

    1994-01-01

    Spring diatom blooms in temperate waters are often terminated by aggregation of the cells into large floes and subsequent mass sedimentation of the phytoplankton to the sea floor. The rate of aggregate formation by physical coagulation depends on the concentration of suspended particles, on the t......Spring diatom blooms in temperate waters are often terminated by aggregation of the cells into large floes and subsequent mass sedimentation of the phytoplankton to the sea floor. The rate of aggregate formation by physical coagulation depends on the concentration of suspended particles...

  6. Host-parasite arms race in mutation modifications: indefinite escalation despite a heavy load?

    Science.gov (United States)

    Haraguchi, Y; Sasaki, A

    1996-11-21

    If constantly changing genotypes are favorable in host and parasite coevolution, an indefinite escalation of mutation rates would result despite heavy mutational loads. We theoretically study this possibility by examining the mutation modifier dynamics of host and parasite that engage in genotype-specific epidemiological interaction. In the first model, we study the evolutionarily stable (ESS) mutation rate or switching rate if two alleles in a single locus are subjected to frequency-dependent selection favoring the rarer of the two. Mutation modifier locus is either tightly linked or unlinked to the selected locus. Sufficiently strong frequency-dependent selection may cause cycles in allele frequencies and a modifier with higher mutation rate enjoys the long-term advantage by randomizing the genotype of their offspring. Through the repeated events of invasion and replacement of mutation modifiers, the mutation rate continues to increase until the allele frequencies are stabilized. If some fraction of mutations are deleterious, there is no longer a pure ESS mutation rate: the evolutionarily stable population then consists of multiple strains concerning mutation modifier, typically one with a very high mutation rate and the other with a very low rate, stably coexisting and fighting off invasion by any other modifiers. These results are almost independent of the linkage between the selected and the modifier loci. In the second model, we consider the joint evolution of host and parasite mutation modifiers, assuming that a specific pair of host and parasite genotype densities change following the Nicholson-Bailey type model. If there is no cost of deleterious mutations, mutation rates of both species are escalated indefinitely by modifier evolution until they completely suppress the fluctuation of genotype densities. However, a small cost of deleterious mutation is enough to collapse this coevolutionary equilibrium of inflated mutations. Typical coevolutionary outcome

  7. Molecular Aggregation in Disodium Cromoglycate

    Science.gov (United States)

    Singh, Gautam; Agra-Kooijman, D.; Collings, P. J.; Kumar, Satyendra

    2012-02-01

    Details of molecular aggregation in the mesophases of the anti-asthmatic drug disodium cromoglycate (DSCG) have been studied using x-ray synchrotron scattering. The results show two reflections, one at wide angles corresponding to π-π stacking (3.32 å) of molecules, and the other at small angles which is perpendicular to the direction of molecular stacking and corresponds to the distance between the molecular aggregates. The latter varies from 35 - 41 å in the nematic (N) phase and 27 -- 32 å in the columnar (M) phase. The temperature evolution of the stack height, positional order correlations in the lateral direction, and orientation order parameter were determined in the N, M, and biphasic regions. The structure of the N and M phases and the nature of the molecular aggregation, together with their dependence on temperature and concentration, will be presented.

  8. SHAPE CHARACTERIZATION OF CONCRETE AGGREGATE

    Directory of Open Access Journals (Sweden)

    Jing Hu

    2011-05-01

    Full Text Available As a composite material, the performance of concrete materials can be expected to depend on the properties of the interfaces between its two major components, aggregate and cement paste. The microstructure at the interfacial transition zone (ITZ is assumed to be different from the bulk material. In general, properties of conventional concrete have been found favoured by optimum packing density of the aggregate. Particle size is a common denominator in such studies. Size segregation in the ITZ among the binder particles in the fresh state, observed in simulation studies by concurrent algorithm-based SPACE system, additionally governs density as well as physical bonding capacity inside these shell-like zones around aggregate particles. These characteristics have been demonstrated qualitatively pertaining also after maturation of the concrete. Such properties of the ITZs have direct impact on composite properties. Despite experimental approaches revealed effects of aggregate grain shape on different features of material structure (among which density, and as a consequence on mechanical properties, it is still an underrated factor in laboratory studies, probably due to the general feeling that a suitable methodology for shape characterization is not available. A scientific argument hindering progress is the interconnected nature of size and shape. Presently, a practical problem preventing shape effects to be emphasized is the limitation of most computer simulation systems in concrete technology to spherical particles. New developments at Delft University of Technology will make it possible in the near future to generate jammed states, or other high-density fresh particle mixtures of non-spherical particles, which thereupon can be subjected to hydration algorithms. This paper will sketch the outlines of a methodological approach for shape assessment of loose (non-embedded aggregate grains, and demonstrate its use for two types of aggregate, allowing

  9. Biogenic silica dissolution in diatom aggregates: insights from reactive transport modelling

    KAUST Repository

    Moriceau, B

    2014-12-15

    © Inter-Research 2014. Diatom aggregates contribute significantly to the vertical sinking flux of particulate matter in the ocean. These fragile structures form a specific microhabitat for the aggregated cells, but their internal chemical and physical characteristics remain largely unknown. Studies on the impact of aggregation on the Si cycle led to apparent inconsistency. Despite a lower biogenic silica (bSiO2) dissolution rate and diffusion of the silicic acid (dSi) being similar in aggregates and in sea-water, dSi surprisingly accumulates in aggregates. A reaction-diffusion model helps to clarify this incoherence by reconstructing dSi accumulation measured during batch experiments with aggregated and non-aggregated Skeletonema marinoi and Chaetoceros decipiens. The model calculates the effective bSiO2 dissolution rate as opposed to the experimental apparent bSiO2 dissolution rate, which is the results of the effective dissolution of bSiO2 and transport of dSi out of the aggregate. In the model, dSi transport out of the aggregate is modulated by alternatively considering retention (decrease of the dSi diffusion constant) and adsorption (reversible chemical bonds between dSi and the aggregate matrix) processes. Modelled bSiO2 dissolution is modulated by the impact of dSi concentration inside aggregates and diatom viability, as enhanced persistence of metabolically active diatoms has been observed in aggregates. Adsorption better explains dSi accumulation within and outside aggregates, raising the possible importance of dSi travelling within aggregates to the deep sea (potentially representing 20% of the total silica flux). The model indicates that bSiO2 dissolution is effectively decreased in aggregates mainly due to higher diatom viability but also to other parameters discussed herein.

  10. Environmentalism and natural aggregate mining

    Science.gov (United States)

    Drew, L.J.; Langer, W.H.; Sachs, J.S.

    2002-01-01

    Sustaining a developed economy and expanding a developing one require the use of large volumes of natural aggregate. Almost all human activity (commercial, recreational, or leisure) is transacted in or on facilities constructed from natural aggregate. In our urban and suburban worlds, we are almost totally dependent on supplies of water collected behind dams and transported through aqueducts made from concrete. Natural aggregate is essential to the facilities that produce energy-hydroelectric dams and coal-fired powerplants. Ironically, the utility created for mankind by the use of natural aggregate is rarely compared favorably with the environmental impacts of mining it. Instead, the empty quarries and pits are seen as large negative environmental consequences. At the root of this disassociation is the philosophy of environmentalism, which flavors our perceptions of the excavation, processing, and distribution of natural aggregate. The two end-member ideas in this philosophy are ecocentrism and anthropocentrism. Ecocentrism takes the position that the natural world is a organism whose arteries are the rivers-their flow must not be altered. The soil is another vital organ and must not be covered with concrete and asphalt. The motto of the ecocentrist is "man must live more lightly on the land." The anthropocentrist wants clean water and air and an uncluttered landscape for human use. Mining is allowed and even encouraged, but dust and noise from quarry and pit operations must be minimized. The large volume of truck traffic is viewed as a real menace to human life and should be regulated and isolated. The environmental problems that the producers of natural aggregate (crushed stone and sand and gravel) face today are mostly difficult social and political concerns associated with the large holes dug in the ground and the large volume of heavy truck traffic associated with quarry and pit operations. These concerns have increased in recent years as society's demand for

  11. Aggregating energy flexibilities under constraints

    DEFF Research Database (Denmark)

    Valsomatzis, Emmanouil; Pedersen, Torben Bach; Abello, Alberto

    2016-01-01

    The flexibility of individual energy prosumers (producers and/or consumers) has drawn a lot of attention in recent years. Aggregation of such flexibilities provides prosumers with the opportunity to directly participate in the energy market and at the same time reduces the complexity of scheduling...... the energy units. However, aggregated flexibility should support normal grid operation. In this paper, we build on the flex-offer (FO) concept to model the inherent flexibility of a prosumer (e.g., a single flexible consumption device such as a clothes washer). An FO captures flexibility in both time...

  12. Balancing energy flexibilities through aggregation

    DEFF Research Database (Denmark)

    Valsomatzis, Emmanouil; Hose, Katja; Pedersen, Torben Bach

    2014-01-01

    One of the main goals of recent developments in the Smart Grid area is to increase the use of renewable energy sources. These sources are characterized by energy fluctuations that might lead to energy imbalances and congestions in the electricity grid. Exploiting inherent flexibilities, which exist...... in both energy production and consumption, is the key to solving these problems. Flexibilities can be expressed as flex-offers, which due to their high number need to be aggregated to reduce the complexity of energy scheduling. In this paper, we discuss balance aggregation techniques that already during...

  13. In vivo amyloid aggregation kinetics tracked by time-lapse confocal microscopy in real-time.

    Science.gov (United States)

    Villar-Piqué, Anna; Espargaró, Alba; Ventura, Salvador; Sabate, Raimon

    2016-01-01

    Amyloid polymerization underlies an increasing number of human diseases. Despite this process having been studied extensively in vitro, aggregation is a difficult process to track in vivo due to methodological limitations and the slow kinetics of aggregation reactions in cells and tissues. Herein we exploit the amyloid properties of the inclusions bodies (IBs) formed by amyloidogenic proteins in bacteria to address the kinetics of in vivo amyloid aggregation. To this aim we used time-lapse confocal microscopy and a fusion of the amyloid-beta peptide (A β42) with a fluorescent reporter. This strategy allowed us to follow the intracellular kinetics of amyloid-like aggregation in real-time and to discriminate between variants exhibiting different in vivo aggregation propensity. Overall, the approach opens the possibility to assess the impact of point mutations as well as potential anti-aggregation drugs in the process of amyloid formation in living cells.

  14. Stratification of extracellular polymeric substances (EPS) for aggregated anammox microorganisms.

    Science.gov (United States)

    Jia, Fangxu; Yang, Qing; Liu, Xiuhong; Li, Xiyao; Li, Baikun; Zhang, Liang; Peng, Yongzhen

    2017-02-27

    Sludge aggregation and biofilm formation are the most effective approaches to solve the washout of anammox microorganisms. In this study, the structure and composition of EPS (extracellular polymeric substances) were investigated to elucidate the factors for the anammox aggregation property. Anammox sludge taken from 18 lab-scale and pilot-scale reactors treating different types of wastewater was analyzed using EEM-PARAFAC (excitation-emission matrix and parallel factor analysis), FTIR (fourier transform infrared spectroscopy) and real-time PCR combined with multivariate statistical analysis. The results showed that slime and TB-EPS (tightly bound EPS) were closely related with water quality and sludge morphology, and could be used as the indicators for anammox microbial survival ability and microbial aggregate morphology. Furthermore, slime secreted from anammox bacterial cells may be exhibited higher viscosity to the sludge surface and easily formed the gel network to aggregate. Large amounts of hydrophobic groups of protein in TB-EPS promoted the microbial aggregation. The mechanisms of anammox aggregation explored in this study enhanced the understanding of anammox stability in wastewater treatment processes.

  15. Aggregated IgG inhibits the differentiation of human fibrocytes.

    Science.gov (United States)

    Pilling, Darrell; Tucker, Nancy M; Gomer, Richard H

    2006-06-01

    Fibrocytes are fibroblast-like cells, which appear to participate in wound healing and are present in pathological lesions associated with asthma, pulmonary fibrosis, and scleroderma. Fibrocytes differentiate from CD14+ peripheral blood monocytes, and the presence of serum delays this process dramatically. We previously purified the factor in serum, which inhibits fibrocyte differentiation, and identified it as serum amyloid P (SAP). As SAP binds to Fc receptors for immunoglobulin G (IgG; Fc gammaRs), Fc gammaR activation may be an inhibitory signal for fibrocyte differentiation. Fc gammaR are activated by aggregated IgG, and we find aggregated but not monomeric, human IgG inhibits human fibrocyte differentiation. Monoclonal antibodies that bind to Fc gammaRI (CD64) or Fc gammaRII (CD32) also inhibit fibrocyte differentiation. Aggregated IgG lacking Fc domains or aggregated IgA, IgE, or IgM do not inhibit fibrocyte differentiation. Incubation of monocytes with SAP or aggregated IgG inhibited fibrocyte differentiation. Using inhibitors of protein kinase enzymes, we show that Syk- and Src-related tyrosine kinases participate in the inhibition of fibrocyte differentiation. These observations suggest that fibrocyte differentiation can occur in situations where SAP and aggregated IgG levels are low, such as the resolution phase of inflammation.

  16. Reward devaluation and heroin escalation is associated with differential expression of CRF signaling genes.

    Science.gov (United States)

    McFalls, Ashley J; Imperio, Caesar G; Bixler, Georgina; Freeman, Willard M; Grigson, Patricia Sue; Vrana, Kent E

    2016-05-01

    One of the most damaging aspects of drug addiction is the degree to which natural rewards (family, friends, employment) are devalued in favor of seeking, obtaining and taking drugs. We have utilized an animal model of reward devaluation and heroin self-administration to explore the role of the coricotropin releasing factor (CRF) pathway. Given access to a saccharin cue followed by the opportunity to self-administer heroin, animals will parse into distinct phenotypes that suppress their saccharin intake (in favor of escalating heroin self-administration) or vice versa. We find that large saccharin suppressors (large heroin takers) demonstrate increased mRNA expression for elements of the CRF signaling pathway (CRF, CRF receptors and CRF binding protein) within the hippocampus, medial prefrontal cortex and the ventral tegmental area. Moreover, there were no gene expression changes of these components in the nucleus accumbens. Use of bisulfite conversion sequencing suggests that changes in CRF binding protein and CRF receptor gene expression may be mediated by differential promoter methylation.

  17. Dose-Escalated Robotic SBRT for Stage I-II Prostate Cancer.

    Science.gov (United States)

    Meier, Robert

    2015-01-01

    Stereotactic body radiotherapy (SBRT) is the precise external delivery of very high-dose radiotherapy to targets in the body, with treatment completed in one to five fractions. SBRT should be an ideal approach for organ-confined prostate cancer because (I) dose-escalation should yield improved rates of cancer control; (II) the unique radiobiology of prostate cancer favors hypofractionation; and (III) the conformal nature of SBRT minimizes high-dose radiation delivery to immediately adjacent organs, potentially reducing complications. This approach is also more convenient for patients, and is cheaper than intensity-modulated radiotherapy (IMRT). Several external beam platforms are capable of delivering SBRT for early-stage prostate cancer, although most of the mature reported series have employed a robotic non-coplanar platform (i.e., CyberKnife). Several large studies report 5-year biochemical relapse rates which compare favorably to IMRT. Rates of late GU toxicity are similar to those seen with IMRT, and rates of late rectal toxicity may be less than with IMRT and low-dose rate brachytherapy. Patient-reported quality of life (QOL) outcomes appear similar to IMRT in the urinary domain. Bowel QOL may be less adversely affected by SBRT than with other radiation modalities. After 5 years of follow-up, SBRT delivered on a robotic platform is yielding outcomes at least as favorable as IMRT, and may be considered appropriate therapy for stage I-II prostate cancer.

  18. Dose-Escalated Robotic SBRT for Stage I-II Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Robert eMeier

    2015-04-01

    Full Text Available Abstract: Stereotactic body radiotherapy (SBRT is the precise external delivery of very high-dose radiotherapy to targets in the body, with treatment completed in one to five fractions. SBRT should be an ideal approach for organ-confined prostate cancer because (I dose escalation should yield improved rates of cancer control; (II the unique radiobiology of prostate cancer favors hypofractionation and (III the conformal nature of SBRT minimizes high-dose radiation delivery to immediately adjacent organs, potentially reducing complications. This approach is also more convenient for patients, and is cheaper than intensity modulated radiotherapy (IMRT. Several external beam platforms are capable of delivering SBRT for early-stage prostate cancer, although most of the mature reported series have employed a robotic non-coplanar platform (i.e., CyberKnife. Several large studies report 5-year biochemical relapse rates which compare favorably to IMRT. Rates of late GU toxicity are similar to those seen with IMRT, and rates of late rectal toxicity may be less than with IMRT and low dose rate (LDR brachytherapy. Patient-reported quality of life (QOL outcomes appear similar to IMRT in the urinary domain. Bowel QOL may be less adversely affected by SBRT than with other radiation modalities. After five years of follow-up, SBRT delivered on a robotic platform is yielding outcomes at least as favorable as IMRT, and may be considered appropriate therapy for stage I-II prostate cancer.

  19. Importance of appropriate initial antibiotic therapy and de-escalation in the treatment of nosocomial pneumonia

    Directory of Open Access Journals (Sweden)

    J. Rello

    2007-08-01

    Full Text Available Inappropriate initial antibiotic therapy in nosocomial pneumonia is associated with higher mortality, longer hospital stays and increased healthcare costs. The key pathogens associated with these adverse outcomes include Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus and Acinetobacter baumannii. Due to the increasing rates of resistance, a new paradigm is needed for treating nosocomial infections in the intensive care unit (ICU. Optimal initial therapy consists of a broad-spectrum antibiotic started in a timely manner and administered at the correct dose and via the correct route. Because pathogen aetiology and resistance patterns vary from one ICU to another, recommendations for initial therapy should be tailored to each institution. Selection of the broad-spectrum antibiotic should be based on the patient's risk factors (including comorbidities, duration of ventilation and recent antibiotic exposure, suspected pathogen and up-to-date local resistance patterns. After 48–72 h, the patient should be reassessed and antibiotic therapy de-escalated based on the microbiological results and the clinical response.

  20. Anticipatory 50 kHz ultrasonic vocalizations are associated with escalated alcohol intake in dependent rats.

    Science.gov (United States)

    Buck, Cara L; Malavar, Jordan C; George, Olivier; Koob, George F; Vendruscolo, Leandro F

    2014-09-01

    Rats emit 50kHz ultrasonic vocalizations (USVs) in situations of increased motivation, such as during the anticipation of palatable food or drugs of abuse. Whether the same holds true for the anticipation of alcohol intake remains unknown. Alcohol drinking in a nondependent state is thought to be mediated by its rewarding effects (positive reinforcement), whereas drinking in the dependent state is motivated by alcohol's stress-relieving effects (negative reinforcement). Here, we measured context-elicited 50kHz USVs in alcohol-dependent (alcohol vapor-exposed) and nondependent rats immediately before operant alcohol self-administration sessions. Dependent rats showed escalated levels of alcohol intake compared with nondependent rats. Overall, dependent and nondependent rats showed similar levels of anticipatory 50kHz USVs. However, the number of anticipatory USVs was positively correlated with alcohol intake in dependent rats but not nondependent rats. Additionally, dependent rats with higher alcohol intake displayed increased anticipatory 50kHz USVs compared with rats that had lower alcohol intake, whereas no difference was observed between rats with high and low alcohol intake in the nondependent group. Increased 50kHz USVs were specific for the anticipation of alcohol self-administration and did not generalize to a novel environment. These findings suggest that anticipatory 50kHz USVs may be an indicator of context-elicited negative reinforcement learning.

  1. Hydrogeologic assessment of escalating groundwater exploitation in the Indus Basin, Pakistan

    Science.gov (United States)

    Khan, S.; Rana, T.; Gabriel, H. F.; Ullah, Muhammad K.

    2008-12-01

    Groundwater development has contributed significantly to food security and reduction in poverty in Pakistan. Due to rapid population growth there has been a dramatic increase in the intensity of groundwater exploitation leading to declining water tables and deteriorating groundwater quality. In such prevailing conditions, the hydrogeological appraisal of escalating groundwater exploitation has become of paramount importance. Keeping this in view, a surface water-groundwater quantity and quality model was developed to assess future groundwater trends in the Rechna Doab (RD), a sub-catchment of the Indus River Basin. Scenario analysis shows that if dry conditions persist, there will be an overall decline in groundwater levels of around 10 m for the whole of RD during the next 25 years. The lower parts of RD with limited surface water supplies will undergo the highest decline in groundwater levels (10 to 20 m), which will make groundwater pumping very expensive for farmers. There is a high risk of groundwater salinization due to vertical upconing and lateral movement of highly saline groundwater into the fresh shallow aquifers in the upper parts of RD. If groundwater pumping is allowed to increase at the current rate, there will be an overall decline in groundwater salinity for the lower and middle parts of RD because of enhanced river leakage.

  2. 自动扶梯的历史%The History of the Escalator

    Institute of Scientific and Technical Information of China (English)

    David A.Cooper; 马英俊

    2000-01-01

    1859年,纳森·艾母兹发明了自动扶梯的第1个专利.这在当时是很超前的,因为第1台电动机是在19世纪70的年终逐出来的.在之后的80年代,西伯格、列诺、哈利、惠勒、道奇发展了自动扶梯这一事业.西伯格将elevatus(上升)和scale(梯级)合二为一创造出来自动扶梯(escalator)这一名词.那时,Otis公司是自司生产经营有冲突且是唯一有资格使用大写E开头拼写Escalator的公司.1911年,伦敦地铁安装了其第1台自动扶梯.自动扶梯迷人的历史从1859年发明以来延续至今.

  3. Biological equivalent dose studies for dose escalation in the stereotactic synchrotron radiation therapy clinical trials

    Energy Technology Data Exchange (ETDEWEB)

    Prezado, Y.; Fois, G.; Edouard, M.; Nemoz, C.; Renier, M.; Requardt, H.; Esteve, F.; Adam, JF.; Elleaume, H.; Bravin, A., E-mail: prezado@esrf.fr [ID17 Biomedical Beamline, European Synchrotron Radiation Facility (ESRF), 6 rue Jules Horowitz, BP 220, 38043 Grenoble Cedex (France)

    2009-03-15

    Synchrotron radiation is an innovative tool for the treatment of brain tumors. In the stereotactic synchrotron radiation therapy (SSRT) technique a radiation dose enhancement specific to the tumor is obtained. The tumor is loaded with a high atomic number (Z) element and it is irradiated in stereotactic conditions from several entrance angles. The aim of this work was to assess dosimetric properties of the SSRT for preparing clinical trials at the European Synchrotron Radiation Facility (ESRF). To estimate the possible risks, the doses received by the tumor and healthy tissues in the future clinical conditions have been calculated by using Monte Carlo simulations (PENELOPE code). The dose enhancement factors have been determined for different iodine concentrations in the tumor, several tumor positions, tumor sizes, and different beam sizes. A scheme for the dose escalation in the various phases of the clinical trials has been proposed. The biological equivalent doses and the normalized total doses received by the skull have been calculated in order to assure that the tolerance values are not reached.

  4. Tomotherapy PET-guided dose escalation. A dosimetric feasibility study for patients with malignant pleural mesothelioma

    Energy Technology Data Exchange (ETDEWEB)

    Maggio, Angelo; Cutaia, Claudia; Di Dia, Amalia; Bresciani, Sara; Miranti, Anna; Poli, Matteo; Stasi, Michele [Candiolo Cancer Institute - FPO, IRCCS, Medical Physics, Turin (Italy); Del Mastro, Elena; Garibaldi, Elisabetta; Gabriele, Pietro [Candiolo Cancer Institute - FPO, IRCCS, Radiotherapy Department, Turin (Italy)

    2016-02-15

    The aim of this study was to investigate whether a safe escalation of the dose to the pleural cavity and PET/CT-positive areas in patients with unresectable malignant pleural mesothelioma (MPM) is possible using helical tomotherapy (HT). We selected 12 patients with MPM. Three planning strategies were investigated. In the first strategy (standard treatment), treated comprised a prescribed median dose to the planning target volume (PTV) boost (PTV{sub 1}) of 64.5 Gy (range: 56 Gy/28 fractions to 66 Gy/30 fractions) and 51 Gy (range: 50.4 Gy/28 fractions to 54 Gy/30 fractions) to the pleura PTV (PTV{sub 2}). Thereafter, for each patient, two dose escalation plans were generated prescribing 62.5 and 70 Gy (2.5 and 2.8 Gy/fraction, respectively) to the PTV{sub 1} and 56 Gy (2.24 Gy/fraction) to the PTV{sub 2}, in 25 fractions. Dose-volume histogram (DVH) constraints and normal tissue complication probability (NTCP) calculations were used to evaluate the differences between the plans. For all plans, the 95 % PTVs received at least 95 % of the prescribed dose. For all patients, it was possible to perform the dose escalation in accordance with the Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) constraints for organs at risk (OARs). The average contralateral lung dose was < 8 Gy. NTCP values for OARs did not increase significantly compared with the standard treatment (p > 0.05), except for the ipsilateral lung. For all plans, the lung volume ratio was strongly correlated with the V{sub 20}, V{sub 30}, and V{sub 40} DVHs of the lung (p < 0.0003) and with the lung mean dose (p < 0.0001). The results of this study suggest that by using HT it is possible to safely escalate the dose delivery to at least 62.5 Gy in PET-positive areas while treating the pleural cavity to 56 Gy in 25 fractions without significantly increasing the dose to the surrounding normal organs. (orig.) [German] Ziel war es, zu untersuchen, ob mit der helikalen Tomotherapie (HT) eine

  5. Incorporating a Patient Dichotomous Characteristic in Cancer Phase I Clinical Trials Using Escalation with Overdose Control

    Directory of Open Access Journals (Sweden)

    Mourad Tighiouart

    2012-01-01

    Full Text Available We describe a design for cancer phase I clinical trials that takes into account patients heterogeneity thought to be related to treatment susceptibility. The goal is to estimate the maximum tolerated dose (MTD given patient’s specific dichotomous covariate value. The design is Bayesian adaptive and is an extension of escalation with overdose control (EWOC. We will assess the performance of this method by comparing the following designs via extensive simulations: (1 design using a covariate; patients are accrued to the trial sequentially and the dose given to a patient depends on his/her baseline covariate value, (2 design ignoring the covariate; patients are accrued to the trial sequentially and the dose given to a patient does not depend on his/her baseline covariate value, and (3 design using separate trials; in each group, patients are accrued to the trial sequentially and EWOC is implemented in each group. These designs are compared with respect to safety of the trial and efficiency of the estimates of the MTDs via extensive simulations. We found that ignoring a significant baseline binary covariate in the model results in a substantial number of patients being overdosed. On the other hand, accounting for a nonsignificant covariate in the model has practically no effect on the safety of the trial and efficiency of the estimates of the MTDs.

  6. Real Option Method and Escalation of Commitment in the Evaluation of Investment Projects

    Directory of Open Access Journals (Sweden)

    Mehrdad Karami

    2011-01-01

    Full Text Available Problem statement: This study applies an experimental method to find out whether using the real option method along with the discounted cash flow techniques can reduce the decision-makers’ Escalation of Commitment (EC hereafter or their desire to keep up their commitment to a failed project. Approach: The real option method used for the evaluation of long-term projects also measures the flexibility value which may be produced during the implementation of the project. Results: The results indicate that those who use the real option method show lower EC to a failed project than those who merely use the net present value method. Conclusion/Recommendations: The major conclusion might be that using the real option method in capital budgeting can affect the users’ behavior and decisions and lead to better decision-making in the long-term projects. In view of the fact that longterm investment projects are costly and time-consuming, a greater need is felt for better methods of evaluating such projects and, in consequence, researchers should also consider the other affective aspects of using real method options on the users' behavior and decisions.

  7. Medicinal Chemistry Focusing on Aggregation of Amyloid-β.

    Science.gov (United States)

    Sohma, Youhei

    2016-01-01

    The aggregation of peptides/proteins is intimately related to a number of human diseases. More than 20 have been identified which aggregate into fibrils containing extensive β-sheet structures, and species generated in the aggregation processes (i.e., oligomers and fibrils) contribute to disease development. Amyloid-β peptide (designated Aβ), related to Alzheimer's disease (AD), is the representative example. The intensive aggregation property of Aβ also leads to difficulty in its synthesis. To improve the synthetic problem, we developed an O-acyl isopeptide of Aβ1-42, in which the N-acyl linkage (amide bond) of Ser(26) was replaced with an O-acyl linkage (ester bond) at the side chain. The O-acyl isopeptide demonstrated markedly higher water-solubility than that of Aβ1-42, while it quickly converted to intact monomer Aβ1-42 via an O-to-N acyl rearrangement under physiological conditions. Inhibition of the pathogenic aggregation of Aβ1-42 might be a therapeutic strategy for curing AD. We succeeded in the rational design and identification of a small molecule aggregation inhibitor based on a pharmacophore motif obtained from cyclo[-Lys-Leu-Val-Phe-Phe-]. Moreover, the inhibition of Aβ aggregation was achieved via oxygenation (i.e., incorporation of oxygen atoms to Aβ) using an artificial catalyst. We identified a selective, cell-compatible photo-oxygenation catalyst of Aβ, a flavin catalyst attached to an Aβ-binding peptide, which markedly decreased the aggregation potency and neurotoxicity of Aβ.

  8. Quantitative investigations of aggregate systems.

    Science.gov (United States)

    Rai, D K; Beaucage, G; Jonah, E O; Britton, D T; Sukumaran, S; Chopra, S; Gonfa, G Goro; Härting, M

    2012-07-28

    Nanomaterials with disordered, ramified structure are increasingly being used for applications where low cost and enhanced performance are desired. A particular example is the use in printed electronics of inorganic conducting and semiconducting nanoparticles. The electrical, as well as other physical properties depend on the arrangement and connectivity of the particles in such aggregate systems. Quantification of aggregate structure and development of structure/property relationships is difficult and progress in the application of these materials in electronics has mainly been empirical. In this paper, a scaling model is used to parameterize the structure of printed electronic layers. This model has chiefly been applied to polymers but surprisingly it shows applicability to these nanolayers. Disordered structures of silicon nanoparticles forming aggregates are investigated using small angle x-ray scattering coupled with the scaling model. It is expected that predictions using these structural parameters can be made for electrical properties. The approach may have wide use in understanding and designing nano-aggregates for electronic devices.

  9. Diversity, intent, and aggregated search

    NARCIS (Netherlands)

    M. de Rijke

    2014-01-01

    Diversity, intent and aggregated search are three core retrieval concepts that receive significant attention. In search result diversification one typically considers the relevance of a document in light of other retrieved documents. The goal is to identify the probable "aspects" of an ambiguous que

  10. Cyclosporine A enhances platelet aggregation.

    Science.gov (United States)

    Grace, A A; Barradas, M A; Mikhailidis, D P; Jeremy, J Y; Moorhead, J F; Sweny, P; Dandona, P

    1987-12-01

    In view of the reported increase in thromboembolic episodes following cyclosporine A (CyA) therapy, the effect of this drug on platelet aggregation and thromboxane A2 release was investigated. The addition of CyA, at therapeutic concentrations to platelet rich plasma from normal subjects in vitro was found to increase aggregation in response to adrenaline, collagen and ADP. Ingestion of CyA by healthy volunteers was also associated with enhanced platelet aggregation. The CyA-mediated enhancement of aggregation was further enhanced by the addition in vitro of therapeutic concentrations of heparin. Platelets from renal allograft recipients treated with CyA also showed hyperaggregability and increased thromboxane A2 release, which were most marked at "peak" plasma CyA concentration and less so at "trough" concentrations. Platelet hyperaggregability in renal allograft patients on long-term CyA therapy tended to revert towards normal following the replacement of CyA with azathioprine. Hypertensive patients with renal allografts on nifedipine therapy had normal platelet function and thromboxane release in spite of CyA therapy. These observations suggest that CyA-mediated platelet activation may contribute to the pathogenesis of the thromboembolic phenomena associated with the use of this drug. The increased release of thromboxane A2 (a vasoconstrictor) may also play a role in mediating CyA-related nephrotoxicity.

  11. Looking forward and looking back: integrating completion and sunk-cost effects within an escalation-of-commitment progress decision.

    Science.gov (United States)

    Moon, H

    2001-02-01

    Currently, there are 2 conflicting frameworks with which to understand why decision makers might escalate their commitment to a previously chosen course of action: sunk costs and project completion. The author proposes that sunk costs and need to complete exert simultaneous pressures, both independent and interactive, on a decision maker's level of commitment. The responses of 340 participants were analyzed and supported a complementary relationship between the 2 predictors. In addition, sunk costs demonstrated a curvilinear influence on commitment and an interaction with level of completion that supported a Level of Completion x Sunk Cost moderation model. (A marginal utility model was not supported.) Results are discussed in terms of their relevance toward offering a complementary view of 2 potential antecedents to a decision maker's propensity to escalate his or her commitment to a previously chosen course of action.

  12. Integrated boost IMRT with FET-PET-adapted local dose escalation in glioblastomas. Results of a prospective phase II study

    Energy Technology Data Exchange (ETDEWEB)

    Piroth, M.D.; Pinkawa, M.; Holy, R. [RWTH Aachen University Hospital (Germany). Dept. of Radiation Oncology; Forschungszentrum Juelich GmbH (DE). Juelich-Aachen Research Alliance (JARA) - Section JARA-Brain] (and others)

    2012-04-15

    Dose escalations above 60 Gy based on MRI have not led to prognostic benefits in glioblastoma patients yet. With positron emission tomography (PET) using [{sup 18}F]fluorethyl-L-tyrosine (FET), tumor coverage can be optimized with the option of regional dose escalation in the area of viable tumor tissue. In a prospective phase II study (January 2008 to December 2009), 22 patients (median age 55 years) received radiochemotherapy after surgery. The radiotherapy was performed as an MRI and FET-PET-based integrated-boost intensity-modulated radiotherapy (IMRT). The prescribed dose was 72 and 60 Gy (single dose 2.4 and 2.0 Gy, respectively) for the FET-PET- and MR-based PTV-FET{sub (72 Gy)} and PTV-MR{sub (60 Gy)}. FET-PET and MRI were performed routinely for follow-up. Quality of life and cognitive aspects were recorded by the EORTC-QLQ-C30/QLQ Brain20 and Mini-Mental Status Examination (MMSE), while the therapy-related toxicity was recorded using the CTC3.0 and RTOG scores. Median overall survival (OS) and disease-free survival (DFS) were 14.8 and 7.8 months, respectively. All local relapses were detected at least partly within the 95% dose volume of PTV-MR{sub (60 Gy)}. No relevant radiotherapy-related side effects were observed (excepted alopecia). In 2 patients, a pseudoprogression was observed in the MRI. Tumor progression could be excluded by FET-PET and was confirmed in further MRI and FET-PET imaging. No significant changes were observed in MMSE scores and in the EORTC QLQ-C30/QLQ-Brain20 questionnaires. Our dose escalation concept with a total dose of 72 Gy, based on FET-PET, did not lead to a survival benefit. Acute and late toxicity were not increased, compared with historical controls and published dose-escalation studies. (orig.)

  13. Novel Aggregative Adherence Fimbria Variant of Enteroaggregative Escherichia coli

    DEFF Research Database (Denmark)

    Jønsson, Rie; Struve, Carsten; Boisen, Nadia

    2015-01-01

    Enteroaggregative Escherichia coli (EAEC) organisms belong to a diarrheagenic pathotype known to cause diarrhea and can be characterized by distinct aggregative adherence (AA) in a stacked-brick pattern to cultured epithelial cells. In this study, we investigated 118 EAEC strains isolated from...

  14. Strategic Stability Reconsidered: Prospects for Escalation and Nuclear War in the Middle East

    Energy Technology Data Exchange (ETDEWEB)

    Russell, J.A.

    2009-07-01

    for survival'. The paper first draws upon Thomas Schelling's ideas to assess the regional strategic framework, and finds systemic uncertainties which suggest that escalation by various parties - state and non-state actors - is a possible outcome. Both near-term and long-term scenarios are considered. The near-term nuclear use scenarios are all predicated on the assumption that nuclear use will occur within the context of escalation to or within war. As dangerous as these circumstances are, longer-term scenarios for nuclear use will also be proposed, which, like the alarming near-term scenarios, flow from the same unstable regional dynamics. The Middle East's unstable dynamics occur within a global environment characterized by a general sense of insecurity about various nuclear issues. Reflecting this situation, the Bulletin of Atomic Scientists recently moved its 'Doomsday Clock' from seven- to five minutes to midnight - the most advanced setting since 1981. Citing Iran's nuclear ambitions, North Korea's test of a nuclear weapon, the failure to secure nuclear materials, a controversial U.S. nuclear doctrine that some argue suggests an expanded role for nuclear weapons, and the continued presence of 26,000 nuclear weapons in the United States and Russia, the Bulletin expressed new concerns about global strategic stability. These developments occurred against a backdrop of the collapse of the 2005 Nonproliferation Treaty Review conference due, among other things, to disinterest in the global community in supporting the spread of nonproliferation norms. (author)

  15. Decision Regret in Men Undergoing Dose-Escalated Radiation Therapy for Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Steer, Anna N. [Department of Radiation Oncology, North Coast Cancer Institute, Coffs Harbour (Australia); Aherne, Noel J., E-mail: noel.aherne@ncahs.health.nsw.gov.au [Department of Radiation Oncology, North Coast Cancer Institute, Coffs Harbour (Australia); Rural Clinical School Faculty of Medicine, University of New South Wales, Coffs Harbour (Australia); Gorzynska, Karen; Hoffman, Matthew; Last, Andrew; Hill, Jacques [Department of Radiation Oncology, North Coast Cancer Institute, Coffs Harbour (Australia); Shakespeare, Thomas P. [Department of Radiation Oncology, North Coast Cancer Institute, Coffs Harbour (Australia); Rural Clinical School Faculty of Medicine, University of New South Wales, Coffs Harbour (Australia)

    2013-07-15

    Purpose: Decision regret (DR) is a negative emotion associated with medical treatment decisions, and it is an important patient-centered outcome after therapy for localized prostate cancer. DR has been found to occur in up to 53% of patients treated for localized prostate cancer, and it may vary depending on treatment modality. DR after modern dose-escalated radiation therapy (DE-RT) has not been investigated previously, to our knowledge. Our primary aim was to evaluate DR in a cohort of patients treated with DE-RT. Methods and Materials: We surveyed 257 consecutive patients with localized prostate cancer who had previously received DE-RT, by means of a validated questionnaire. Results: There were 220 responses (85.6% response rate). Image-guided intensity modulated radiation therapy was given in 85.0% of patients and 3-dimensional conformal radiation therapy in 15.0%. Doses received included 73.8 Gy (34.5% patients), 74 Gy (53.6%), and 76 Gy (10.9%). Neoadjuvant androgen deprivation (AD) was given in 51.8% of patients and both neoadjuvant and adjuvant AD in 34.5%. The median follow-up time was 23 months (range, 12-67 months). In all, 3.8% of patients expressed DR for their choice of treatment. When asked whether they would choose DE-RT or AD again, only 0.5% probably or definitely would not choose DE-RT again, compared with 8.4% for AD (P<.01). Conclusion: Few patients treated with modern DE-RT express DR, with regret appearing to be lower than in previously published reports of patients treated with radical prostatectomy or older radiation therapy techniques. Patients experienced more regret with the AD component of treatment than with the radiation therapy component, with implications for informed consent. Further research should investigate regret associated with individual components of modern therapy, including AD, radiation therapy and surgery.

  16. Dose-Escalation Study for Cardiac Radiosurgery in a Porcine Model

    Energy Technology Data Exchange (ETDEWEB)

    Blanck, Oliver, E-mail: oliver.blanck@uksh.de [Department of Radiation Oncology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); CyberKnife Center Northern Germany, Guestrow (Germany); Bode, Frank [Medical Department II, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Gebhard, Maximilian [Institute of Pathology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Hunold, Peter [Department of Radiology and Nuclear Medicine, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Brandt, Sebastian [Department of Anaesthesiology and Intensive Care Medicine, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Bruder, Ralf [Institute for Robotics and Cognitive Systems, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Grossherr, Martin [Department of Anaesthesiology and Intensive Care Medicine, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Vonthein, Reinhard [Institute of Medical Biometry and Statistics, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Rades, Dirk [Department of Radiation Oncology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Dunst, Juergen [Department of Radiation Oncology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); University Copenhagen (Denmark)

    2014-07-01

    Purpose: To perform a proof-of-principle dose-escalation study to radiosurgically induce scarring in cardiac muscle tissue to block veno-atrial electrical connections at the pulmonary vein antrum, similar to catheter ablation. Methods and Materials: Nine mini-pigs underwent pretreatment magnetic resonance imaging (MRI) evaluation of heart function and electrophysiology assessment by catheter measurements in the right superior pulmonary vein (RSPV). Immediately after examination, radiosurgery with randomized single-fraction doses of 0 and 17.5-35 Gy in 2.5-Gy steps were delivered to the RSPV antrum (target volume 5-8 cm{sup 3}). MRI and electrophysiology were repeated 6 months after therapy, followed by histopathologic examination. Results: Transmural scarring of cardiac muscle tissue was noted with doses ≥32.5 Gy. However, complete circumferential scarring of the RSPV was not achieved. Logistic regressions showed that extent and intensity of fibrosis significantly increased with dose. The 50% effective dose for intense fibrosis was 31.3 Gy (odds ratio 2.47/Gy, P<.01). Heart function was not affected, as verified by MRI and electrocardiogram evaluation. Adjacent critical structures were not damaged, as verified by pathology, demonstrating the short-term safety of small-volume cardiac radiosurgery with doses up to 35 Gy. Conclusions: Radiosurgery with doses >32.5 Gy in the healthy pig heart can induce circumscribed scars at the RSPV antrum noninvasively, mimicking the effect of catheter ablation. In our study we established a significant dose-response relationship for cardiac radiosurgery. The long-term effects and toxicity of such high radiation doses need further investigation in the pursuit of cardiac radiosurgery for noninvasive treatment of atrial fibrillation.

  17. Escalation, retreat, and female indifference as alternative outcomes of sexually antagonistic coevolution.

    Science.gov (United States)

    Rowe, Locke; Cameron, Erin; Day, Troy

    2005-05-01