bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficacy of Posaconazole against Three Clinical
Aspergillus fumigatus
Isolates with Mutations in the
cyp51A
Gene
Authors: Mavridou Eleftheria , Brüggemann Roger J. M. , Melchers Willem J. G. , Mouton Johan W. , Verweij Paul E. 
Published: November 2009

ABSTRACT

The
in vivo
efficacy of posaconazole against 4 clinical
Aspergillus fumigatus
isolates with posaconazole MICs ranging from 0.03 to 16 mg/liter, as determined by CLSI method M38A, was assessed in a nonneutropenic murine model of disseminated aspergillosis. The underlying resistance mechanisms of the isolates included substitutions in the
cyp51A
gene at codon 220 (M220I), codon 54 (G54W), and codon 98 (L98H). The latter was combined with a 34-bp tandem repeat in the gene promoter region (TR L98H). The control isolate exhibited a wild-type phenotype without any known resistance mechanism. Oral posaconazole therapy was started 24 h after infection and was given once daily for 14 consecutive days. Mice were treated with four different doses (1 to 64 mg/kg of body weight), and survival was used as the end point. Survival was dependent both on the dose and on the MIC. The Hill equation with a variable slope fitted the relationship between the dose/MIC ratio and 14-day survival well (
R
2
, 0.92), with a 50% effective dose (ED
50
) of 29.0 mg/kg (95% confidence interval [CI], 15.6 to 53.6 mg/kg). This also applied to the relationship between the area under the plasma concentration-time curve (AUC)/MIC ratio and 14-day survival (50% effective pharmacodynamic index [EI
50
], 321.3 [95% CI, 222.7 to 463.4]). Near-maximum survival was reached at an AUC/MIC ratio of nearly 1,000. These results indicate that treatment of infections with
A. fumigatus
strains for which MICs are 0.5 mg/liter requires doses exceeding the present licensed doses. Increasing the standard dosing regimen may have some effect and may be clinically useful if no alternatives are available.
Cellular Pharmacology of the Anti-Hepatitis B Virus Agent β-l-2′,3′-Didehydro-2′,3′-Dideoxy-N4-Hydroxycytidine: Relevance for Activation in HepG2 Cells
Authors: Matthes E. , Bünger H. 
Published: November 2009

ABSTRACTß-l-2′,3′-Didehydro-2′,3′-dideoxy-N4-hydroxycytidine (l-Hyd4C) was demonstrated to be an effective and highly selective inhibitor of hepatitis B virus (HBV) replication in HepG2.2.15 cells (50% effective dose [ED50] = 0.03 μM; 50% cytotoxic dose [CD50] = 2,500 μM). In the present study, we investigated the intracellular pharmacology of tritiatedl-Hyd4C in HepG2 cells.l-[3H]Hyd4C was shown to be phosphorylated extensively and rapidly to the 5′-mono-, 5′-di-, and 5′-triphosphate derivatives. Other metabolites deriving from a reduction or removal of the NHOH group ofl-Hyd4C could not be detected, although both reactions were described as the primary catabolic pathways of the stereoisomer ß-d-N4-hydroxycytidine in HepG2 cells. Also, the formation of liponucleotide metabolites, such as the 5′-diphosphocholine derivative ofl-Hyd4C, as described for somel-deoxycytidine analogues, seems to be unlikely. After incubation of HepG2 cells with 10 μMl-[3H]Hyd4C for 24 h, the 5′-triphosphate accumulated to 19.4 ± 2.7 pmol/106cells. The predominant peak belonged to 5-diphosphate, with 43.5 ± 4.3 pmol/106cells. The intracellular half-life of the 5′-triphosphate was estimated to be 29.7 h. This extended half-life probably reflects a generally low affinity of 5′-phosphorylatedl-deoxycytidine derivatives for phosphate-degrading enzymes but may additionally be caused by an efficient rephosphorylation of the 5′-diphosphate during a drug-free incubation. The high 5′-triphosphate level and its extended half-life in HepG2 cells are consistent with the potent antiviral activity ofl-Hyd4C.
Novel Insights about Class 2 Integrons from Experimental and Genomic Epidemiology
Authors: Ramírez María Soledad , Piñeiro Silvia , Centrón Daniela 
Published: November 2009

ABSTRACT

In order to contribute to the knowledge of the architecture and epidemiology of class 2 integrons, we performed a class 2 integron molecular survey in which we analyzed 726 isolates in two bacterial populations from environmental and nonepidemiologically related clinical samples, respectively, collected from 1982 to 2007. We recovered the
intI2
gene from 130 of 726 isolates, most of which were clinical isolates, and only 1 (a psychrophilic
Pseudomonas
sp.) was from a water sample. Unlike the widespread distribution of class 1 integrons within Gram-negative bacilli, only
Acinetobacter baumannii
and
Enterobacter cloacae
harbored class 2 integrons at a high frequency in our collection. Class 2 integrons with six novel cassette arrays were documented. Characterization of the transposition module of Tn
7
, the genetic platform in which class 2 integrons have always been reported, showed
tns
modules with a mosaic genetic structure. A bioinformatic analysis performed with the
tns
genes present in sequence databases, the finding of
intI2
not associated with
tns
genes, and the genetic examination of novel
tns
-like genes found in three isolates indicated the possibility of the independent evolution of the two components related to horizontal gene transfer, the class 2 integrons and the Tn
7
transposons.
Helicobacter pyloriStimulates Dendritic Cells To Induce Interleukin-17 Expression from CD4+T Lymphocytes
Authors: Khamri Wafa , Walker Marjorie M. , Clark Peter , Atherton John C. , Thursz Mark R. , Bamford Kathleen B. , Lechler Robert I. , Lombardi Giovanna 
Published: November 2009

ABSTRACTHelicobacter pyloriis a human gastroduodenal pathogen that leads to active chronic inflammation characterized by T-cell responses biased toward a Th1 phenotype. It has been accepted thatH. pyloriinfection induces a Th17 response. At mucosal sites, dendritic cells (DCs) have the capacity to induce effector T cells. Here, we evaluate the role of DCs in theH. pylori-induced interleukin-17 (IL-17) response. Immunohistochemistry and immunofluorescence were performed on human gastric mucosal biopsy samples and showed that myeloid DCs inH. pylori-infected patients colocalized with IL-23- and that IL-17-producing lymphocytes were present inH. pylori-infected antral biopsy samples. In parallel, human monocyte-derived DCs stimulatedin vitrowith liveH. pyloricells produced significant levels of IL-23 in the absence of IL-12 release. The subsequent incubation ofH. pylori-infected DCs with autologous CD4+T cells led to gamma interferon (IFN-γ) and IL-17 expression. The inhibition of IL-1 and, to a lesser extent, IL-23 inhibited IL-17 production by T cells. Finally, isogenicH. pylorimutant strains not expressing major virulence factors were less effective in inducing IL-1 and IL-23 release by DCs and IL-17 release by T cells than parental strains. Altogether, we can conclude that DCs are potent inducers of IL-23/IL-17 expression followingH. pyloristimulation. IL-1/IL-23 as well asH. pylorivirulence factors seem to play an important role in mediating this response.
Major Secretory Antigens of the Helminth
Fasciola hepatica
Activate a Suppressive Dendritic Cell Phenotype That Attenuates Th17 Cells but Fails To Activate Th2 Immune Responses
Authors: Dowling David J. , Hamilton Clare M. , Donnelly Sheila , La Course James , Brophy Peter M. , Dalton John , O'Neill Sandra M. 
Published: November 2009

ABSTRACT

Fasciola hepatica
is a helminth pathogen that drives Th2/Treg immune responses in its mammalian host. The parasite releases a large number of molecules that are critical to inducing this type of immune response. Here we have selected recombinant forms of two major
F. hepatica
secreted molecules, the protease cathepsin L (rFhCL1) and an antioxidant, sigma class glutathione transferase (rFhGST-si), to examine their interactions with dendritic cells (DCs). Despite enzymatic and functional differences between these molecules, both induced interleukin-6 (IL-6), IL-12p40, and macrophage inflammatory protein 2 (MIP-2) secretion from DCs and enhanced CD40 expression. While this induction was mediated by Toll-like receptor 4 (TLR4), the subsequent intracellular signaling pathways differed; rFhCL1 signaled through p38, and rFhGST-si mediated its effect via c-Jun N-terminal kinase (JNK), p38, p-NF-κBp65, and IRF5. Neither rFhCL1 nor rFhGST-si enhanced DC phagocytosis or induced Th2 immune responses
in vivo
. However, DCs matured in the presence of either enzyme attenuated IL-17 production from OVA peptide-specific T cells
in vivo
. In addition, DCs exposed to either antigen secreted reduced levels of IL-23. Therefore, both
F. hepatica
FhCL1 and FhGST-si modulate host immunity by suppressing responses associated with chronic inflammation—an immune modulatory mechanism that may benefit the parasite's survival within the host.
Aspergillus fumigatus
LaeA-Mediated Phagocytosis Is Associated with a Decreased Hydrophobin Layer
Authors: Dagenais Taylor R. T. , Giles Steve S. , Aimanianda Vishukumar , Latgé Jean-Paul , Hull Christina M. , Keller Nancy P. 
Published: November 2009

ABSTRACT

Aspergillus fumigatus
is the causal agent of the life-threatening disease invasive aspergillosis.
A. fumigatus laeA
deletants, aberrant in toxin biosynthesis and spore development, are decreased in virulence. Among other characteristics, the decreased virulence is associated with increased spore susceptibility to macrophage phagocytosis. Three characteristics, cell wall microbe-associated molecular patterns (MAMPs), secreted metabolites, and rodlet content, thought to be important in macrophage
-Aspergillus
spore interactions were examined. Flow cytometry analysis of wild-type and
ΔlaeA
spores did not reveal any differences in surface-accessible MAMPs, including β-(1,3)-glucan, α-mannose, chitin, and other carbohydrate ligands. Blocking experiments with laminarin and mannan supported the conclusion that differences in cell wall carbohydrates were not responsible for enhanced
ΔlaeA
spore phagocytosis.
Aspergillus
spores have been reported to secrete metabolites affecting phagocytosis. Neither spent culture exchange, transwell, nor coincubation internalization experiments supported a role for secreted metabolites in the differential uptake of wild-type and
ΔlaeA
spores. However, sonication assays implicated a role for surface rodlet protein/hydrophobin (RodAp) in differential spore phagocytosis. A possible role of RodAp in enhanced
ΔlaeA
spore uptake was further assessed by RodAp extraction and quantification, where wild-type spores were found to contain 60% more RodAp than
ΔlaeA
spores. After removal of the surface rodlet layer, wild-type spores were phagocytosed at similar rates as
ΔlaeA
spores. We conclude that increased uptake of
ΔlaeA
resting spores is not associated with changes in secreted metabolite production of this mutant or surface carbohydrate availability but, rather, due to a decrease in the surface RodAp content of
ΔlaeA
spores. We theorize that RodAp acts as an antiphagocytic molecule, possibly via physicochemical means and/or by impeding MAMP recognition by macrophage receptors.
Invasion of Melanoma Cells byMycoplasma hyorhinis: Enhancement by Protease Treatment
Authors: Kornspan Jonathan D. , Tarshis Mark , Rottem Shlomo 
Published: November 2009

ABSTRACTMycoplasma hyorhinis(strain MCLD) was recently isolated from a melanoma cell culture. Growth of MCLD was considerably improved by 24 serial passages in a modified Hayflick's mycoplasma medium. Transmission electron microscopy showed that MCLD exhibits a polymorphic appearance, with ovoid or elongated cells frequently harboring an electron-dense core at one of the poles. Adherence ofM. hyorhinisto melanoma cells followed saturation kinetics. Furthermore, althoughM. hyorhinishas been considered to remain attached to the surface of the host cells, we show for the first time, qualitatively by confocal laser scanning microscopy and quantitatively by a gentamicin resistance assay, that MCLD is able to invade melanoma cells. The ingested mycoplasmas were randomly distributed in the cytoplasm, tending to concentrate near the plasma membrane. Both adherence to and invasion of melanoma cells byM. hyorhinisstrain MCLD were dramatically enhanced by mild proteolytic digestion with proteinase K (2.5 μg/mg cell protein for 2.5 min at 37°C) that affected the surface-exposed proteins of this organism, mainly the major 47-kDa lipoprotein. We suggest that the intracellular location ofM. hyorhinisstrain MCLD is a privileged niche, which may explain the survival ofM. hyorhinisin tissue cultures. The enhanced binding to and invasion of melanoma cells by protease treatment may be due to either the activation or the enhanced exposure of an adhesin(s) on the mycoplasmal cell surface.
Efficient Serum Clearance of Botulinum Neurotoxin Achieved Using a Pool of Small Antitoxin Binding Agents
Authors: Sepulveda Jorge , Mukherjee Jean , Tzipori Saul , Simpson Lance L. , Shoemaker Charles B. 
Published: November 2009

ABSTRACTAntitoxins for botulinum neurotoxins (BoNTs) and other toxins are needed that can be produced economically with improved safety and shelf-life properties compared to conventional therapeutics with large-animal antisera. Here we show that protection from BoNT lethality and rapid BoNT clearance through the liver can be elicited in mice by administration of a pool of epitope-tagged small protein binding agents together with a single anti-tag monoclonal antibody (MAb). The protein binding agents used in this study were single-chain Fv domains (scFvs) with high affinity for BoNT serotype A (BoNT/A). The addition of increasing numbers of differently tagged scFvs synergistically increased the level of protection against BoNT/A. It was not necessary that any of the BoNT/A binding agents possess toxin-neutralizing activity. Mice were protected from a dose equivalent to 1,000 to 10,000 50% lethal doses (LD50) of BoNT/A when given three or four different anti-BoNT scFvs, each fused to an E-tag peptide, and an anti-E-tag IgG1 MAb. Toxin protection was enhanced when an scFv contained two copies of the E tag. Pharmacokinetic studies demonstrated that BoNT/A was rapidly cleared from the sera of mice given a pool of anti-BoNT/A scFvs and an anti-tag MAb but not from the sera of mice given scFvs alone or anti-tag MAb alone. The scFv pool and anti-tag MAb protected mice from lethality when administered up to 2 h following exposure of mice to a dose equivalent to 10 LD50of BoNT/A. These results suggest that it will be possible to rapidly and economically develop and produce therapeutic antitoxins consisting of pools of tagged binding agents that are administered with a single, stockpiled anti-tag MAb.
THE GRAVITATIONAL FIELD OF A PLANE SLAB
Authors: GAMBOA SARAVÍ RICARDO E. 
Published: November 2009

We discuss the exact solution to Einstein's equation corresponding to a static and plane symmetric distribution of matter with constant positive density located below z = 0 matched to vacuum solutions. The internal solution depends essentially on two constants: the density ρ and a parameter κ. We show that these space–times finish down below at an inner singularity at finite depth [Formula: see text]. We show that for κ ≥ 0.3513 ⋯, the dominant energy condition is satisfied all over the space–time. We match these singular solutions to the vacuum one and compute the external gravitational field in terms of slab's parameters. Depending on the value of κ, these slabs are either attractive, repulsive or neutral. The external solution turns out to be a Rindler's space–time. Repulsive slabs explicitly show how negative, but finite pressure can dominate the attraction of the matter. In this case, the presence of horizons in the vacuum shows that there are null geodesics which never reach the surface of the slab. We also consider a static and plane symmetric nonsingular distribution of matter with constant positive density ρ and thickness [Formula: see text] surrounded by two external vacuums. We explicitly write down the pressure and the external gravitational fields in terms of ρ and d. The solution turns out to be attractive and remarkably asymmetric: the "upper" solution is Rindler's vacuum, whereas the "lower" one is the singular part of Taub's plane symmetric solution. Inside the slab, the pressure is positive and bounded, presenting a maximum at an asymmetrical position between the boundaries. We show that if [Formula: see text], the dominant energy condition is satisfied all over the space–time. We also show how the mirror symmetry is restored at the Newtonian limit. We also find thinner repulsive slabs by matching a singular slice of the inner solution to the vacuum. We also discuss solutions in which an attractive slab and a repulsive one, and two neutral ones are joined. We also discuss how to assemble a "gravitational capacitor" by inserting a slice of vacuum between two such slabs.
Leukocyte urokinase plasminogen activator receptor and PSGL1 play a role in endogenous arterial fibrinolysis
Authors: Bai Xufang , Weitz Jeffrey , Gross Peter 
Published: November 2009

SummaryFibrin is an integral component of arterial thrombi. Using a mouse model of arteriolar thrombosis, high-speed fluorescence microscopy reveals that, within minutes, the fibrin content of thrombi rapidly increases and then decreases.The decrease in fibrin coincides with leukocyte binding to the thrombi, a process mediated by the interaction of leukocyte P-selectin glycoprotein ligand-1 (PSGL-1) with P-selectin on the surface of activated platelets. Because leukocytes possess urokinase-type plasminogen activator (uPA) activity,we used mice deficient in uPA or the uPA receptor (uPAR) to explore the contribution of leukocyte associated uPA to the loss of fibrin from these thrombi. Fibrin loss in both uPA-deficient mice and uPAR-deficient mice was reduced compared with that in wild-type controls.Transfusion of leukocytes from wild-type mice into uPAR-deficient mice restored fibrin loss to levels similar to that in wild-type mice. In contrast, transfusion of leukocytes from mice deficient in uPAR or PSGL-1 did not enhance fibrin loss. Thus, fibrin loss from microarteriolar thrombi is mediated, at least in part, by leukocyte-associated uPA in a process that requires leukocyte uPAR and PSGL-1.
Effect of antiplatelet therapy on inflammatory markers in atherothrombotic patients
Authors: Muhlestein Joseph 
Published: November 2009

SummaryInflammation is central to the pathogenesis and progression of atherosclerosis and thrombosis, the underlying cause of major cardiovascular disease. Platelets, in addition to their role in haemostasis, play a key role in both thrombus formation and inflammation following vascular injury, especially atherosclerotic lesions. An increasing body of evidence suggests that inhibition of platelet function can modulate inflammatory markers, particularly those associated with activated platelets, such as CD40 ligand, P-selectin, and C-reactive protein. The currently available antiplatelet agents aspirin, clopidogrel, prasugrel, abciximab, and eptifibatide have shown varying effects on inflammatory markers. These effects seem to be mostly indirect, i.e. mediated primarily through reduced platelet activation that results in reduced inflammatory marker expression. However, there is some evidence that suggests direct effects (i.e. those independent of platelets) may also play a role in modulating inflammatory markers. Evidence linking inflammation and thrombosis supports the hypothesis that agents with both anti-inflammatory and antiplatelet effects may reduce vascular inflammation and limit acute and long-term thrombotic events. An assessment of the involvement of inflammatory mediators in atherosclerosis may provide further insight into important predictive markers of cardiovascular outcomes that may also serve as potential therapeutic targets. This review examines the evidence for and potential clinical relevance of the effects of antiplatelet therapy on inflammatory markers.
Long- and short-term in vitro D-dimer stability measured with INNOVANCE D-Dimer
Authors: Böhm-Weigert Martina , Wissel Thomas , Muth Heidrun , Kemkes-Matthes Bettina , Peetz Dirk 
Published: November 2009

Summary
In vitro D-dimer stability in plasma is widely assumed, but has not yet been documented by systematic studies using samples covering a wide range of D-dimer. We investigated the short- and long-term stability of D-dimer in clinical citrated plasma samples with normal and pathological levels. The short-term stability was analysed by measuring D-dimer fresh, after storage of plasma for 4 hours at room temperature (RT) and after an additional 24 h storage at +2 to +8°C (n=40). Long-term stability samples (n=40) were measured fresh and after storage for 19, 25 and 36 months at ≤-60°C. The effect of repeated freezing was analysed by measuring samples (n=50) fresh and after four consecutive freeze-thaw cycles. D-dimer was measured on the BCS System using the INNOVANCE D-Dimer assay (Siemens Healthcare Diagnostics Products GmbH, Marburg, Germany). D-dimer values at baseline ranged from 0.23–22.2 mg/l FEU. The mean percentage change after storage for 4 hours at RT and additional 24 hours at +2 to +8°C was +3.8% and +2.7%, respectively. The mean percentage change after frozen storage for 19, 25 and 36 months at ≤-60°C was –11.7%, –4.8% and –9.3%, respectively. The small decrease of D-dimer values after frozen storage was not time-dependent. Repeated freezing did not significantly alter D-dimer values (mean change ≤5%). The data demonstrate stability of D-dimer in plasma prior to freezing for up to 4 hours at RT and for up to 24 hours at +2 to +8°C as well as in plasma stored for up to three years at ≤-60°C.
Coagulation disorders and the risk of retinal vein occlusion
Authors: Scharrer Inge , Lüchtenberg Marc , Hattenbach Lars-Olof , Kuhli-Hattenbach Claudia 
Published: November 2009

SummaryOver the past years, there has been a dramatic increase in the number of identifiable causes of thrombophilia. However, to date, there are no large, prospective studies to assess an optimal, cost-effective approach with regard to screening and case finding for thrombophilic risk factors in patients presenting with retinal vessel occlusion. Two hundred twenty-eight patients with retinal vein occlusion (RVO) and 130 age-matched healthy controls were prospectively screened for thrombophilic risk factors. Both cohorts were divided into three subgroups, depending on the patients‘ age at the time of the RVO or a previous thromboembolic event. Patient age ≤45 years was associated with a high prevalence of coagulation disorders (p<0.0001). Among patients ≤45 years and >45 to ≤60 years, a family history of thromboembolism was strongly associated with the presence of thrombophilic disorders. The absence of cardiovascular risk factors was found to be a strong predictor for the presence of coagulation disorders in all patient groups (≤45 years, p=0.003; >45 to ≤60 years, p=0.0008; >60 years, p=0.001). Multivariate analysis revealed the presence of resistance to activated protein C (p=0.014), antiphospholipid antibodies (p=0.022), and deficiency of the anticoagulant proteins (p=0.05) as independent risk factors for the development of RVO among patients ≤45 years. Our results indicate that thrombophilic disorders are associated with the development of retinal vein occlusion in patients ≤45 years by the time of the RVO or a previous thromboembolic event, in patients with a family history of thromboembolism, or in patients without cardiovascular risk factors.