Conditions for Transient Viremia in Deterministic in-Host Models: Viral Blips Need No Exogenous Trigger

2013 ◽  
Vol 73 (2) ◽  
pp. 853-881 ◽  
Author(s):  
Wenjing Zhang ◽  
Lindi M. Wahl ◽  
Pei Yu
Keyword(s):  
Exogenous Trigger

Lack of Hcv Infection in Malignant, Cells Refutes the Hypothesis of a Direct Transforming Action of the Virus in the Pathogenesis of Hcv-Associated B-Cell Nhls

2002 ◽  
Vol 88 (5) ◽  
pp. 400-406 ◽  
Author(s):  
Salvatore De Vita ◽  
Valli De Re ◽  
Domenico Sansonno ◽  
Annunziata Gloghini ◽  
Daniela Gasparotto ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Hcv Infection ◽  
Low Grade ◽  
Immunoglobulin Gene ◽  
Pathogenetic Role ◽  
Exogenous Trigger ◽  
Grade One ◽  
Hodgkin's Lymphomas

Aims and background Preliminary evidence suggests that hepatitis C virus (HCV) might play a pathogenetic role in autoimmune-related, non-malignant B-cell lymphoproliferation, as well as in a subset of B-cell non-Hodgkin's lymphomas (NHLs). With regard to the mechanism(s) by which HCV might favor B-cell expansion and malignant transformation, most data support an indirect pathogenetic role of the virus as an exogenous trigger. A direct oncogenetic role of HCV by direct cell infection and deregulation has only been hypothesized on the basis of the lymphotropism of the virus. Methods In this study we investigated the possible HCV infection of NHL B cells by means of sensitive and quantitative polymerase chain reaction (PCR) on affinity-purified neoplastic cells, and by HCV-specific immunohistochemistry and in situ hybridization. Results HCV infection of neoplastic B cells was documented in only three cases, namely the low-grade B-cell NHLs that arose in the course of mixed cryoglobulinemia syndrome (MC). HCV infection, below one viral genome per cell, was detectable only by PCR. All the remaining low-grade (one case) and high-grade B-cell NHLs (two cases) were HCV uninfected. Previous immunoglobulin gene analyses were consistent with an antigen-driven B-cell lymphoproliferation in the studied cases. Conclusions Overall, our data are consistent with an indirect oncogenetic role of HCV in B-cell lymphomagenesis as an exogenous trigger. Infection of B cells by HCV appears possible in some NHL subsets, but the implications remain unknown.

scholarly journals Explaining the Selection of Routines for Change during Organizational Search

2016 ◽  
Vol 61 (4) ◽  
pp. 551-583 ◽  
Author(s):  
Amit Nigam ◽  
Ruthanne Huising ◽  
Brian Golden
Keyword(s):  
Participant Observation ◽  
Organizational Adaptation ◽  
Focus Attention ◽  
The People ◽  
Organizational Search ◽  
Shape Selection ◽  
Role Based ◽  
Exogenous Trigger ◽  
Strategic Framing ◽  
Selection Of

We examine how organizations select some routines to be changed, but not others, during organizational search. Selection is a critical step that links an exogenous trigger for change, change in individual routines, and larger processes of organizational adaptation. Drawing on participant observation of an initiative to improve perioperative efficiency in seven Ontario hospitals, we find that organizational roles shape selection by influencing both politics and frames in organizational search. Roles shape politics by defining the role-specific goals of the people who have authority to change a routine. Organizations will not select a routine for change unless at least some elites—people with role-based authority—frame the existing routine as negatively affecting their role-specific goals. Roles also shape individuals’ frames. Because people are only partially exposed to interdependencies between routines in their day-to-day work, they may not be fully aware of the diverse impact that an existing routine can have on their goals. Proponents for change can use strategic framing to focus attention on interdependencies between routines to get elites to better see how an existing routine negatively affects their goals. They can also change elites’ goals by using strategic framing to focus attention on new and broader goals that the change in routine would promote.

scholarly journals Effect of an exogenous trigger on the pathogenesis of lupus in (NZB × NZW)F1mice

2002 ◽  
Vol 46 (8) ◽  
pp. 2235-2244 ◽  
Author(s):  
Hideo Yoshida ◽  
Minoru Satoh ◽  
Krista M. Behney ◽  
Chee-Gun Lee ◽  
Hanno B. Richards ◽  
...  
Keyword(s):  
Exogenous Trigger

scholarly journals ATP keeps exocytosis sites in a primed state but is not required for membrane fusion: an analysis with Paramecium cells in vivo and in vitro.

1986 ◽  
Vol 103 (4) ◽  
pp. 1279-1288 ◽  
Author(s):  
J Vilmart-Seuwen ◽  
H Kersken ◽  
R Stürzl ◽  
H Plattner
Keyword(s):  
Membrane Fusion ◽  
Time Course ◽  
Paramecium Tetraurelia ◽  
Wild Type ◽  
Primed State ◽  
Different Strains ◽  
Exogenous Trigger ◽  
Free Media

We have tried to specify a widespread hypothesis on the requirement of ATP for exocytosis (membrane fusion). With Paramecium tetraurelia cells, synchronously (approximately 1 s) exocytosing trichocysts, ATP pools have been measured in different strains, including wild type cells, "non-discharge" (nd), "trichless" (tl), and other mutations. The occurrence of a considerable and rapid ATP consumption also in nd and tl mutations as well as its time course (with a maximum 3-5 s after exocytosis) in exocytosis-competent strains does not match the actual extent of exocytosis performance. However, from in vivo as well as from in vitro experiments, we came to the conclusion that ATP might be required to keep the system in a primed state and its removal might facilitate membrane fusion. (For the study of exocytosis in vitro we have developed a new system, consisting of isolated cortices). In vivo as well as in vitro exocytosis is inhibited by increased levels of ATP or by a nonhydrolyzable ATP analogue. In vitro exocytosis is facilitated in ATP-free media. In vivo-microinjected ATP retards exocytosis in response to chemical triggers, whereas microinjected apyrase triggers exocytosis without exogenous trigger. Experiments with this system also largely exclude any overlaps with other processes that normally accompany exocytosis. Our data also explain why it was frequently assumed that ATP would be required for exocytosis. We conclude that membrane fusion during exocytosis does not require the presence of ATP; the occurrence of membrane fusion might involve the elimination of ATP from primed fusogenic sites; most of the ATP consumption measured in the course of exocytosis may be due to other effects, probably to recovery phenomena.

scholarly journals Tearable and Fillable Composite Sponges Capable of Heat Generation and Drug Release in Response to Alternating Magnetic Field

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3637
Author(s):  
Koichiro Hayashi ◽  
Atsuto Tokuda ◽  
Jin Nakamura ◽  
Ayae Sugawara-Narutaki ◽  
Chikara Ohtsuki
Keyword(s):  
Magnetic Field ◽  
Drug Release ◽  
Heat Generation ◽  
Culture Medium ◽  
Surgical Repair ◽  
Thermal Therapy ◽  
Alternating Magnetic Field ◽  
Medium Temperature ◽  
Exogenous Trigger ◽  
Tissue Defects

Tearable and fillable implants are used to facilitate surgery. The use of implants that can generate heat and release a drug in response to an exogenous trigger, such as an alternating magnetic field (AMF), can facilitate on-demand combined thermal treatment and chemotherapy via remote operation. In this study, we fabricated tearable sponges composed of collagen, magnetite nanoparticles, and anticancer drugs. Crosslinking of the sponges by heating for 6 h completely suppressed undesirable drug release in saline at 37 °C but allowed drug release at 45 °C. The sponges generated heat immediately after AMF application and raised the cell culture medium temperature from 37 to 45 °C within 15 min. Heat generation was controlled by switching the AMF on and off. Furthermore, in response to heat generation, drug release from the sponges could be induced and moderated. Thus, remote-controlled heat generation and drug release were achieved by switching the AMF on and off. The sponges destroyed tumor cells when AMF was applied for 15 min but not when AMF was absent. The tearing and filling properties of the sponges may be useful for the surgical repair of bone and tissue defects. Moreover, these sponges, along with AMF application, can facilitate combined thermal therapy and chemotherapy.

scholarly journals Change not State: Perceptual coupling in multistable displays reflects transient bias induced by perceptual change

2021 ◽  
Author(s):  
Alexander Pastukhov ◽  
Claus-Christian Carbon
Keyword(s):  
Scene Perception ◽  
Spatial Context ◽  
Perceptual Inference ◽  
Depth Effect ◽  
Selective Visual Attention ◽  
Perceptual Change ◽  
Dominant State ◽  
Kinetic Depth ◽  
Exogenous Trigger ◽  
Perceptual Coupling

AbstractWe investigated how changes in dynamic spatial context influence visual perception. Specifically, we reexamined the perceptual coupling phenomenon when two multistable displays viewed simultaneously tend to be in the same dominant state and switch in accord. Current models assume this interaction reflecting mutual bias produced by a dominant perceptual state. In contrast, we demonstrate that influence of spatial context is strongest when perception changes. First, we replicated earlier work using bistable kinetic-depth effect displays, then extended it by employing asynchronous presentation to show that perceptual coupling cannot be accounted for by the static context provided by perceptually dominant states. Next, we demonstrated that perceptual coupling reflects transient bias induced by perceptual change, both in ambiguous and disambiguated displays. We used a hierarchical Bayesian model to characterize its timing, demonstrating that the transient bias is induced 50–70 ms after the exogenous trigger event and decays within ~200–300 ms. Both endogenous and exogenous switches led to quantitatively and qualitatively similar perceptual consequences, activating similar perceptual reevaluation mechanisms within a spatial surround. We explain how they can be understood within a transient selective visual attention framework or using local lateral connections within sensory representations. We suggest that observed perceptual effects reflect general mechanisms of perceptual inference for dynamic visual scene perception.

Distribution and condition of pueruli of the spiny lobster Jasus edwardsii offshore from north-east New Zealand

2001 ◽  
Vol 52 (8) ◽  
pp. 1211 ◽  
Author(s):  
Andrew G. Jeffs ◽  
Stephen M. Chiswell ◽  
John D. Booth
Keyword(s):  
New Zealand ◽  
Developmental Process ◽  
Spiny Lobster ◽  
Total Lipid Content ◽  
Offshore Water ◽  
North East ◽  
The North ◽  
Jasus Edwardsii ◽  
Phyllosoma Larvae ◽  
Exogenous Trigger

Pelagic spiny lobster, Jasus edwardsii, pueruli and phyllosomas were sampled on offshore transects from the south-east coast of the North Island of New Zealand in February 1998. Carapace length, weight, and total lipid content of pueruli (n = 360) were assessed; 33 pueruli had soft carapaces, indicative of recent metamorphosis from final-stage (stage 11) phyllosoma larvae. The recently metamorphosed pueruli occurred 24–216 km offshore, much farther offshore than has been previously suggested for the location of metamorphosis. Their distribution was compared to information on their size and condition, as well as their distance offshore, water depth, temperature and salinity, and estimates of phytoplankton biomass. The results indicate that a threshold of larval energy reserve is unlikely to trigger metamorphosis, but rather some exogenous trigger may be involved, or metamorphosis may be part of a programmed developmental process. The distribution and condition of the new pueruli suggest that about 84% had the energetic capacity to swim inshore to settle. This result may have important implications for patterns of puerulus settlement and subsequent recruitment of lobsters to coastal populations and their important associated fisheries. It may influence both the seasonal and interannual variability in settlement observed in this species.

Abnormal Heat by Thermal Changing in a D-Pd Gas-Loading System

2012 ◽  
Vol 614-615 ◽  
pp. 253-258 ◽  
Author(s):  
Xin Lu ◽  
Hong Yu Wang ◽  
Jian Tian ◽  
Li Hong Jin ◽  
Bing Jun Shen ◽  
...  
Keyword(s):  
Condensed Phase ◽  
Nuclear Reactions ◽  
Energy Dispersive Spectrometer ◽  
Heat Energy ◽  
Excess Heat ◽  
Loading System ◽  
Loading Ratio ◽  
Exogenous Trigger ◽  
Solid System

In order to explore the condensed phase whether may promote abnormal heating phenomenon and nuclear reactions occur, as well as how to construct and characterization of condensed phase structure filled with deuterium and the use of exogenous trigger transient change. Some deuterium atoms were charged into metal palladium lattice and reached a certain ratio in a D-Pd gas-solid system under the pressure of PD26J heat energy were released in 8 hours, when loading ratio of deuterium x was 0.12, current 8A, pressure 9×104Pa. Improvement of experiment, that excess heat power 41W and 79.58MJ heat energy, which was corresponding to 1.8×104eV for each palladium atom were released in 83 hours and 17 minutes, when current 7.25A, pressure 9×104Pa. An energy dispersive spectrometer (EDS) revealed that new surface topographical features with concentrations of unexpected elements Ag were detected, which implied that the excess heat might come from a nuclear transmutation reaction.

scholarly journals Dynamics of recurrent viral infection

2006 ◽  
Vol 273 (1598) ◽  
pp. 2193-2199 ◽  
Author(s):  
W Yao ◽  
L Hertel ◽  
L.M Wahl
Keyword(s):  
Viral Infection ◽  
Particle Production ◽  
Viral Infections ◽  
T Cell Response ◽  
Chronic Viral Infection ◽  
Viral Production ◽  
Infectious Particle ◽  
Exogenous Factors ◽  
Low Levels ◽  
Exogenous Trigger

In chronic viral infection, low levels of viral replication and infectious particle production are maintained over long periods, punctuated by brief bursts of high viral production and release. We apply well-established principles of modelling virus dynamics to the study of chronic viral infection, demonstrating that a model which incorporates the distinct contributions of cytotoxic T lymphocytes (CTLs) and antibodies exhibits long periods of quiescence followed by brief bursts of viral production. This suggests that for recurrent viral infections, no special mechanism or exogenous trigger is necessary to provoke an episode of reactivation; rather, the system may naturally cycle through recurrent episodes at intervals which can be many years long. We also find that exogenous factors which cause small fluctuations in the natural course of the infection can trigger a recurrent episode. Our model predicts that longer periods between recurrences are associated with more severe viral episodes. Four factors move the system towards less frequent, more severe episodes: decreased viral infectivity, decreased CTL efficacy, decreased memory T cell response and increased antibody efficacy.

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