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Search Results: 1 - 10 of 219566 matches for " Collette C Jonkam "
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Time course of nitric oxide synthases, nitrosative stress, and poly(ADP ribosylation) in an ovine sepsis model
Matthias Lange, Rhykka Connelly, Daniel L Traber, Atsumori Hamahata, Yoshimitsu Nakano, Aimalohi Esechie, Collette Jonkam, Sanna von Borzyskowski, Lillian D Traber, Frank C Schmalstieg, David N Herndon, Perenlei Enkhbaatar
Critical Care , 2010, DOI: 10.1186/cc9097
Abstract: Twenty-four chronically instrumented sheep were subjected to inhalation of 48 breaths of cotton smoke and instillation of live Pseudomonas aeruginosa into both lungs and were euthanized at 4, 8, 12, 18, and 24 hours post-injury. Additional sheep received sham injury and were euthanized after 24 hrs (control). All animals were mechanically ventilated and fluid resuscitated. Lung tissue was obtained at the respective time points for the measurement of neuronal, endothelial, and inducible NOS (nNOS, eNOS, iNOS) mRNA and their protein expression, calcium-dependent and -independent NOS activity, 3-nitrotyrosine (3-NT), and poly(ADP-ribose) (PAR) protein expression.The injury induced severe pulmonary dysfunction as indicated by a progressive decline in oxygenation index and concomitant increase in pulmonary shunt fraction. These changes were associated with an early and transient increase in eNOS and an early and profound increase in iNOS expression, while expression of nNOS remained unchanged. Both 3-NT, a marker of protein nitration, and PAR, an indicator of DNA damage, increased early but only transiently.Identification of the time course of the described pathogenetic factors provides important additional information on the pulmonary response to ALI and sepsis in the ovine model. This information may be crucial for future studies, especially when considering the timing of novel treatment strategies including selective inhibition of NOS isoforms, modulation of peroxynitrite, and PARP.Severe sepsis and septic shock continue to be major causes of morbidity and mortality of ICU patients [1]. Among the sources of nosocomial infections, ICU-acquired pneumonia represents the leading cause of death [2,3]; and Pseudomonas was the second most frequently identified bacteria species causing sepsis among ICU patients in a recent multi-center, observational study [4].Previous studies revealed the important roles of the different isoforms of nitric oxide (NO) synthases (NOS), peroxyn
Pulmonary vascular permeability changes in an ovine model of methicillin-resistant Staphylococcus aureus sepsis
Collette C Jonkam, Kamna Bansal, Daniel L Traber, Atsumori Hamahata, Marc O Maybauer, Dirk M Maybauer, Robert A Cox, Matthias Lange, Rhykka L Connelly, Lillian D Traber, Clarisse D Djukom, John R Salsbury, David N Herndon, Perenlei Enkhbaatar
Critical Care , 2009, DOI: 10.1186/cc7720
Abstract: Ewes were chronically instrumented, and randomised into either a control or MRSA sepsis (MRSA and smoke inhalation) group.Pulmonary function remained stable in the control group, whereas the MRSA sepsis group developed impaired gas exchange and significantly increased lung lymph flow, permeability index and bloodless wet-to-dry weight-ratio (W/D ratio). The plasma nitrate/nitrite (NOx) levels, lung inducible nitric oxide synthases (iNOS) and endothelial nitric oxide synthases (eNOS), vascular endothelial growth factor (VEGF) protein expressions and poly-(ADP)-ribose (PAR) were significantly increased by MRSA challenge.These results provide evidence that excessive NO production may mediate pulmonary vascular hyperpermeability in MRSA sepsis via up regulation of reactive radicals and VEGF.Despite advancements in the treatment of sepsis, its sequelae remain associated with increased risk of death among patients in intensive care units (ICU) [1]. From 1979 to 2000, the incidence of sepsis in the USA increased by 13.7%, and the number of sepsis-related in-hospital deaths rose from 43,579 in 1979 to 120,491 in 2000, with Gram-positive bacteria being increasingly recognised as the most common pathogens (52.1% versus 37.6% Gram negative) [2]. Pneumonia is one of the dominant causes of sepsis. Smoke inhalation injury is frequently complicated by pneumonia [3,4]. The mortality in fire victims increases by a maximum of 20% when associated with smoke inhalation injury alone, by 40% with pneumonia alone, but concomitantly they increase the mortality by up to 60% [4].Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of nosocomial infections in burn patients [5]. Wang and colleagues [6] reported an increased number of patients with community-acquired MRSA bacteraemia and showed a close association with necrotizing pneumonia. Staphylococcus aureus has been reported to be a predominant cause (38%) of ventilator-associated pneumonia (VAP) in surgical ICU
Scaling Analysis and Evolution Equation of the North Atlantic Oscillation Index Fluctuations
C. Collette,M. Ausloos
Physics , 2004, DOI: 10.1142/S0129183104006789
Abstract: The North Atlantic Oscillation (NAO) monthly index is studied from 1825 till 2002 in order to identify the scaling ranges of its fluctuations upon different delay times and to find out whether or not it can be regarded as a Markov process. A Hurst rescaled range analysis and a detrended fluctuation analysis both indicate the existence of weakly persistent long range time correlations for the whole scaling range and time span hereby studied. Such correlations are similar to Brownian fluctuations. The Fokker-Planck equation is derived and Kramers-Moyal coefficients estimated from the data. They are interpreted in terms of a drift and a diffusion coefficient as in fluid mechanics. All partial distribution functions of the NAO monthly index fluctuations have a form close to a Gaussian, for all time lags, in agreement with the findings of the scaling analyses. This indicates the lack of predictive power of the present NAO monthly index. Yet there are some deviations for large (and thus rare) events. Whence suggestions for other measurements are made if some improved predictability of the weather/climate in the North Atlantic is of interest. The subsequent Langevin equation of the NAO signal fluctuations is explicitly written in terms of the diffusion and drift parameters, and a characteristic time scale for these is given in appendix.
Candida albicans Suppresses Nitric Oxide Generation from Macrophages via a Secreted Molecule
John R. Collette, Huaijin Zhou, Michael C. Lorenz
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0096203
Abstract: Macrophages and neutrophils generate a potent burst of reactive oxygen and nitrogen species as a key aspect of the antimicrobial response. While most successful pathogens, including the fungus Candida albicans, encode enzymes for the detoxification of these compounds and repair of the resulting cellular damage, some species actively modulate immune function to suppress the generation of these toxic compounds. We report here that C. albicans actively inhibits macrophage production of nitric oxide (NO). NO production was blocked in a dose-dependent manner when live C. albicans were incubated with either cultured or bone marrow-derived mouse macrophages. While filamentous growth is a key virulence trait, yeast-locked fungal cells were still capable of dose-dependent NO suppression. C. albicans suppresses NO production from macrophages stimulated by exposure to IFN-γ and LPS or cells of the non-pathogenic Saccharomyces cerevisiae. The NO inhibitory activity was produced only when the fungal cells were in direct contact with macrophages, but the compound itself was secreted into the culture media. LPS/IFNγ stimulated macrophages cultured in cell-free conditioned media from co-cultures showed reduced levels of iNOS enzymatic activity and lower amounts of iNOS protein. Initial biochemical characterization of this activity indicates that the inhibitor is a small, aqueous, heat-stable compound. In summary, C. albicans actively blocks NO production by macrophages via a secreted mediator; these findings expand our understanding of phagocyte modulation by this important fungal pathogen and represent a potential target for intervention to enhance antifungal immune responses.
Book Review: Proven Strategies for Building an Information Literacy Program
Collette Saunders
Partnership : the Canadian Journal of Library and Information Practice and Research , 2008,
Abstract:
Book Review: Proven Strategies for Building an Information Literacy Program
Collette Saunders
Partnership : the Canadian Journal of Library and Information Practice and Research , 2008,
Abstract: Review of Proven Strategies for Building an Information Literacy
Book Review: Searching 2.0
Collette Saunders
Partnership : the Canadian Journal of Library and Information Practice and Research , 2009,
Abstract:
Effects of neuronal nitric oxide synthase in ovine lung injury
F Saunders, M Westphal, P Enkhbaatar, J Wang, M Gonzalez, Y Nakano, A Hamahata, C Jonkam, R Connelly, R Cox, H Hawkins, F Schmalstieg, E Horvath, M Lange, C Szabo, L Traber, D Herndon, D Traber
Critical Care , 2007, DOI: 10.1186/cc5176
Abstract: Eleven ewes were surgically instrumented and randomly allocated to either an injured untreated control group (40% total body surface area flame burn and 48 breaths of cotton smoke, n = 6), or an injury group treated with 7-NI (1 mg/kg/hour, n = 5).This insult was associated with systemic inflammation and oxidative stress, as evidenced by a 2.5-fold increase in plasma nitrite/nitrate (NOx) levels, as well as sixfold, twofold, threefold and twofold increases in IL-8, myeloperoxidase (MPO), malondialdehyde (MDA) and poly-ADP-ribose-polymerase (PARP) lung tissue concentrations, respectively. These molecular changes were linked to severe pulmonary derangements. Compared with untreated controls, 7-NI significantly reduced NOx plasma levels (8.4 ± 1 vs 26 ± 10 μmol/l) and decreased IL-8, MPO (3.9 ± 0.2 vs 5.8 ± 0.7 U/g tissue), MDA (2.7 ± 0.3 vs 6.6 ± 1.1 nmol/mg protein) and PARP lung tissue content (3.4 ± 0.7 vs 6.7 ± 0.7), thereby decreasing pulmonary obstruction (12.4 ± 2.2 vs 28.7 ± 5.2 obstruction score) and increasing the PaO2/FiO2 ratio (456 ± 40 vs 313 ± 56, each P < 0.05).These data suggest that nNOS-derived NO plays a pivotal role in the pathophysiology of this double-hit injury and that selective nNOS inhibition may represent a useful approach to attenuate the degree of pulmonary damage.
An unusual occurrence of the Laurentian phyllocarid crustacean Ceratiocaris papilio Salter in the lower Ludfordian (Silurian) of Bohemia (peri-Gondwana)
Budil P,Collette J,Manda ?
Bulletin of Geosciences , 2010, DOI: 10.3140/bull.geosci.1212
Abstract: A rich assemblage (n = 223) of well-preserved phyllocarid crustacean remains is described from offshore calcareous shales of the Kopanina Formation (Silurian, Ludlow, early Ludfordian, Saetograptus linearis Biozone) exposed near the village of V eradice, SE of Beroun. Specimens examined fall within the intraspecific variability of Ceratiocaris papilio Salter in Murchison, 1859, which is widely distributed in the Llandovery and Wenlock of Laurentia. Consequently, the Bohemian specimens represent the first occurrence of C. papilio outside of Laurentia. Additionally, the phyllocarid assemblage from Bohemia is younger than that of Laurentia. In Bohemia, Ceratiocaris papilio occurs in finely laminated calcareous shales. Its abundance varies distinctly from bed to bed, and phyllocarids are the dominant faunal component in only a few beds. Phyllocarids are associated with common graptolites and pelagic orthocerids while other benthic organisms are severely limited. Isolated or articulated furcae and telsons, and isolated mandibles are the most common components of this association, but articulated abdominal segments with caudal appendages (but without carapaces) also occur. An exceptional, slightly disarticulated specimen has articulated abdominal and partial thoracic segments, with mandibles preserved in situ. Additional possible occurrences of C. papilio and related species in Bohemia are also discussed.
Confluent Persistence Revisited
Sebastien Collette,John Iacono,Stefan Langerman
Computer Science , 2011,
Abstract: It is shown how to enhance any data structure in the pointer model to make it confluently persistent, with efficient query and update times and limited space overhead. Updates are performed in $O(\log n)$ amortized time, and following a pointer takes $O(\log c \log n)$ time where $c$ is the in-degree of a node in the data structure. In particular, this proves that confluent persistence can be achieved at a logarithmic cost in the bounded in-degree model used widely in previous work. This is a $O(n/\log n)$-factor improvement over the previous known transform to make a data structure confluently persistent.
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