bluuebunny/crossref_metadata_2025 huggingface dataset:
Electroanatomic Versus Fluoroscopic Mapping for Catheter Ablation Procedures:
Authors: SPORTON SIMON C. , EARLEY MARK J. , NATHAN ANTHONY W. , SCHILLING RICHARD J.
Published: December 2004

Introduction: The aim of this prospective randomized study was to compare the routine use of electroanatomic imaging (CARTO) with that of conventional fluoroscopically guided activation mapping (conventional) in an unselected population referred for catheter ablation. We sought to compare the two approaches with respect to procedure outcome and duration, radiation exposure, and cost.

Methods and Results: All patients undergoing catheter ablation (with the exception of complete AV nodal ablation) were prospectively randomized to either a CARTO or conventional procedure for mapping and ablation. One hundred two patients were randomized. Acute procedural success was similar with either strategy (CARTO vs conventional 43/47 vs 51/55, P > 0.5), as was procedure duration (144 [58] vs 125 [48] min, P = 0.07 (mean [SD]). CARTO was associated with a substantial reduction in fluoroscopy time (9.3 [7.6] vs 28.8 [19.5] min, P < 0.001) and radiation dose (6.2 [6.1] vs 20.8 [32.7] Gray, P = 0.003). CARTO cases used fewer catheters (2.5 [0.7] vs 4.4 [1.1], P < 0.001), but catheter costs were higher (13.8 vs 9.3 units, P < 0.001, where one unit is equivalent to the cost of a nonsteerable quadripolar catheter).

Conclusion: For all catheter ablation procedures, even when a center's “learning curve” for CARTO is included, procedure duration and outcome are similar for CARTO and conventional procedures. CARTO is associated with drastically reduced fluoroscopy time and radiation dose. Although fewer catheters are used with CARTO, catheter costs remain higher. (J Cardiovasc Electrophysiol, Vol. 15, pp. 310‐315, March 2004)
Fatal inflammatory heart disease in a bonobo (Pan paniscus)
Authors: Jones Peter , Mahamba Crispin , Rest Joan , André Claudine
Published: December 2004

Abstract:  We report the first probable identification of encephalomyocarditis virus (EMCV) in a bonobo (Pan paniscus) that had been part of a forest re‐introduction programme. Clinical presentation was of episodic acute on chronic heart failure and cerebral infarction with end‐stage renal failure rather than sudden death which is more commonly associated with EMCV infection. A postmortem diagnosis of probable EMCV was made using gross pathological and histopathological examination. Findings included acute on chronic heart failure combined with the unusual but characteristic histopathological features of non‐suppurative necrotizing myocarditis with mononuclear, inflammatory infiltration of the brain.
Cross fostering in mice: behavioral and physiological carry‐over effects in adulthood
Authors: Bartolomucci A. , Gioiosa L. , Chirieleison A. , Ceresini G. , Parmigiani S. , Palanza P.
Published: December 2004

Cross fostering is a widely used laboratory practice. However, relatively few studies have directly investigated the carry‐over effects of this procedure in adult animals. The aim of the present study is to investigate the late effects of cross fostering (CF) at birth (in litters composed of no siblings) on adult mice. When adults, cross‐fostered male and female mice were examined for intrasex aggression, and levels of emotionality, exploration and anxiety. In addition, body weight was monitored, several internal organs were weighed and plasma corticosterone levels were measured. When compared to controls, body weight of CF male and female mice was increased, at least after early puberty. CF males showed smaller preputial glands, while basal corticosterone level was not affected by cross fostering. In the free‐exploratory test, CF males, but not females, showed a behavioral profile suggestive of lower anxiety. These effects in adulthood cannot be ascribed to differences in the maternal care received, which was not affected by cross fostering. In conclusion, cross fostering at birth induced a number of behavioral and physiological alterations in mice, particularly in males. These findings should be carefully evaluated when applying cross fostering procedure to laboratory animals.
New Multiplex PCR for Rapid Detection of Isoniazid-Resistant
Mycobacterium tuberculosis
Clinical Isolates
Authors: Herrera-León Laura , Molina Tamara , Saíz Pilar , Sáez-Nieto Juan Antonio , Jiménez Maria Soledad
Published: December 2004

In this study, we describe a multiplex PCR to detect a AGC→ACC (serine to threonine) mutation in the
katG
gene and a −15 C-to-T substitution (
inhA
C−15T
) at the 5′ end of a presumed ribosome binding site in the promoter of the
mabA
-
inhA
operon. These mutations have been reported in the majority of previous studies as the most frequent mutations involved in the resistance to isoniazid (INH) of
Mycobacterium tuberculosis
clinical strains with high levels of resistance. The method was optimized and validated after an analysis of 30
M. tuberculosis
clinical isolates with known sequences of the relevant part of the
katG
gene and the regulatory region of the
mabA
-
inhA
operon. We analyzed 297 INH-resistant
M. tuberculosis
isolates collected in Spain from 1996 to 2003 by PCR-restriction fragment length polymorphism (using the
katG
gene), DNA sequencing, and the newly developed multiplex PCR. The results were concordant for all 297 isolates tested. The analysis revealed that 204 (68.7%) of the isolates carried one or both of the mutations. This finding suggests that with further development this multiplex PCR will be able to detect the majority of the INH-resistant
M. tuberculosis
clinical isolates from Spain and other countries where a high frequency of similar mutations occur.
Binding Site of the Bridged Macrolides in the
Escherichia coli
Ribosome
Authors: Xiong Liqun , Korkhin Yakov , Mankin Alexander S.
Published: December 2004

Ketolides represent the latest group of macrolide antibiotics. Tight binding of ketolides to the ribosome appears to correlate with the presence of an extended alkyl-aryl side chain. Recently developed 6,11-bridged bicyclic ketolides extend the spectrum of platforms used to generate new potent macrolides with extended alkyl-aryl side chains. The purpose of the present study was to characterize the site of binding and the action of bridged macrolides in the ribosomes of
Escherichia coli
. All the bridged macrolides investigated efficiently protected A2058 and A2059 in domain V of 23S rRNA from modification by dimethyl sulfate and U2609 from modification by carbodiimide. In addition, bridged macrolides that carry extended alkyl-aryl side chains protruding from the 6,11 bridge protected A752 in helix 35 of domain II of 23S rRNA from modification by dimethyl sulfate. Bridged macrolides efficiently displaced erythromycin from the ribosome in a competition binding assay. The A2058G mutation in 23S rRNA conferred resistance to the bridged macrolides. The U2609C mutation, which renders
E. coli
resistant to the previously studied ketolides telithromycin and cethromycin, barely affected cell susceptibility to the bridged macrolides used in this study. The results of the biochemical and genetic studies indicate that in the
E. coli
ribosome, bridged macrolides bind in the nascent peptide exit tunnel at the site previously described for other macrolide antibiotics. The presence of the side chain promotes the formation of specific interactions with the helix 35 of 23S rRNA.
Drug Resistance Mutations in the Nucleotide Binding Pocket of Human Immunodeficiency Virus Type 1 Reverse Transcriptase Differentially Affect the Phosphorolysis-Dependent Primer Unblocking Activity in the Presence of Stavudine and Zidovudine and Its Inhibition by Efavirenz
Authors: Crespan Emmanuele , Locatelli Giada A. , Cancio Reynel , Hübscher Ulrich , Spadari Silvio , Maga Giovanni
Published: December 2004

Human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) derivatives with D113E, Y115F, F116Y, Q151E/N, and M184V mutations were studied for their phosphorolysis-mediated resistance to the nucleoside RT inhibitors (NRTIs) zidovudine and stavudine and for their inhibition by the nonnucleoside analogs (NNRTIs) efavirenz and nevirapine. The results presented here indicate that these single amino acid substitutions within the nucleotide binding pocket of the viral RT can independently affect different enzymatic properties, such as catalytic efficiency, drug binding, and phosphorolytic activity. Moreover, small local alterations of the physicochemical properties of the microenvironment around the active site can have profound effects on some NRTIs while hardly affecting other ones. In conclusion, even though different mutations within the nucleotide binding pocket of HIV-1 RT can result in a common phenotype (i.e., drug resistance), the molecular mechanisms underlying this phenotype can be very different. Moreover, the same mutation can give rise to different phenotypes depending on the nature of the substrates and/or inhibitors.
The Novel Parainfluenza Virus Hemagglutinin-Neuraminidase Inhibitor BCX 2798 Prevents Lethal Synergism between a Paramyxovirus and
Streptococcus pneumoniae
Authors: Alymova Irina V. , Portner Allen , Takimoto Toru , Boyd Kelli L. , Babu Y. Sudhakara , McCullers Jonathan A.
Published: December 2004

An association exists between respiratory viruses and bacterial infections. Prevention or treatment of the preceding viral infection is a logical goal for reducing this important cause of morbidity and mortality. The ability of the novel, selective parainfluenza virus hemagglutinin-neuraminidase inhibitor BCX 2798 to prevent the synergism between a paramyxovirus and
Streptococcus pneumoniae
was examined in this study. A model of secondary bacterial pneumonia after infection with a recombinant Sendai virus whose hemagglutinin-neuraminidase gene was replaced with that of human parainfluenza virus type 1 [rSV(hHN)] was established in mice. Challenge of mice with a sublethal dose of
S. pneumoniae
7 days after a sublethal infection with rSV(hHN) (synergistic group) caused 100% mortality. Bacterial infection preceding viral infection had no effect on survival. The mean bacterial titers in the synergistic group were significantly higher than in mice infected with bacteria only. The virus titers were similar in mice infected with rSV(hHN) alone and in dually infected mice. Intranasal administration of BCX 2798 at 10 mg/kg per day to the synergistic group of mice starting 4 h before virus infection protected 80% of animals from death. This effect was accompanied by a significant reduction in lung viral and bacterial titers. Treatment of mice 24 h after the rSV(hHN) infection showed no protection against synergistic lethality. Together, our results indicate that parainfluenza viruses can prime for secondary bacterial infections. Prophylaxis of parainfluenza virus infections with antivirals might be an effective strategy for prevention of secondary bacterial complications in humans.
dfrA20
, a Novel Trimethoprim Resistance Gene from
Pasteurella multocida
Authors: Kehrenberg Corinna , Schwarz Stefan
Published: December 2004

A novel trimethoprim resistance gene, designated
dfrA20
, was detected on the 11-kb plasmid pCCK154 from
Pasteurella multocida
. The
dfrA20
gene codes for a dihydrofolate reductase of 169 amino acids. Sequence comparisons revealed that the DfrA20 protein differed distinctly from all dihydrofolate reductases known so far.
In-House Phage Amplification Assay Is a Sound Alternative for Detecting Rifampin-Resistant
Mycobacterium tuberculosis
in Low-Resource Settings
Authors: Símboli Norberto , Takiff Howard , McNerney Ruth , López Beatriz , Martin Anandi , Palomino Juan Carlos , Barrera Lucía , Ritacco Viviana
Published: December 2004

An in-house mycobacteriophage amplification assay for detecting rifampin-resistant
Mycobacterium tuberculosis
showed 100% sensitivity, 97.7% specificity, and 95.2% predictive value for resistance in a test of 129 isolates from a hot spot area of multidrug-resistant
M. tuberculosis
. The applicability of the test was demonstrated in the routine work flow of a low-resource reference laboratory.
In Vivo Resistance of a Laboratory-Selected
Aspergillus fumigatus
Isolate to Amphotericin B
Authors: Manavathu Elias K. , Cutright Jessica L. , Chandrasekar Pranatharthi H.
Published: December 2004

The fungal burdens (number of CFU per pair of lungs) in mice infected with
Aspergillus fumigatus
AB16.4 (for which the amphotericin B [AMB] MIC was elevated) and W73355 (drug-susceptible parent) were reduced by 21 and 81%, respectively, after 5 days of AMB treatment (2 mg/kg/day), indicating that AB16.4 also shows reduced susceptibility to AMB in a murine pulmonary aspergillosis model.
Characterization of In
100
, a New Integron Carrying a Metallo-β-Lactamase and a Carbenicillinase, from
Pseudomonas aeruginosa
Authors: Quinteira Sandra , Sousa João Carlos , Peixe Luísa
Published: December 2004

In
100
, a new integron carrying a carbapenemase gene (
bla
VIM-2
) associated with a carbenicillinase (
blaP1b
) and aminoglycoside resistance genes (
aacA4
and
aadA2
), was detected in a
Pseudomonas aeruginosa
clinical isolate. The particular gene cassette organization of In
100
seems to reflect the evolution of antibiotic usage in therapeutics.
Emergence of Plasmid-Mediated Quinolone Resistance in
Escherichia coli
in Europe
Authors: Mammeri Hedi , Van De Loo Marc , Poirel Laurent , Martinez-Martinez Luis , Nordmann Patrice
Published: December 2004

Although quinolone resistance results mostly from chromosomal mutations, it may also be mediated by a plasmid-encoded
qnr
gene in members of the family
Enterobacteriaceae
. Thus, 297 nalidixic-acid resistant strains of 2,700
Escherichia coli
strains that had been isolated at the Bicêtre Hospital (Le Kremlin-Bicêtre, France) in 2003 were screened for
qnr
by PCR. A single
E. coli
isolate that carried a ca. 180-kb conjugative plasmid encoding a
qnr
determinant was identified. It conferred low-level resistance to quinolones and was associated with a chromosomal mutation in subunit A of the topoisomerase II gene. The
qnr
gene was located on a
sul1
-type class 1 integron just downstream of a conserved region (CR) element (CR1) comprising the Orf513 recombinase. Promoter sequences for
qnr
expression overlapped the extremity of CR1, indicating the role of CR1 in the expression of antibiotic resistance genes. This integron was different from other
qnr
-positive
sul1
-type integrons identified in American and Chinese enterobacterial isolates. In addition, plasmid pQR1 carried another class 1 integron that was identical to In
53
from
E. coli
. The latter integron possessed a series of gene cassettes, including those coding for the extended-spectrum β-lactamase VEB-1, the rifampin ADP ribosyltransferase ARR-2, and several aminoglycoside resistance markers. This is the first report of plasmid-mediated quinolone resistance in Europe associated with an unknown level of plasmid-mediated multidrug resistance in
Enterobacteriaceae
.
Distribution of Antimicrobial Resistance and Virulence-Related Genes among Brazilian Group B Streptococci Recovered from Bovine and Human Sources
Authors: Duarte Rafael S. , Bellei Bruna C. , Miranda Otávio P. , Brito Maria A. V. P. , Teixeira Lúcia M.
Published: December 2004

In the present report we describe the characteristics of 189 antimicrobial-resistant
Streptococcus agalactiae
isolates from bovine (38 isolates) and human (151 isolates) sources. All the strains were resistant to tetracycline (TET), and 16 (8.5%) were also resistant to erythromycin, corresponding to 23.7% of the TET-resistant bovine isolates and 4.6% of the TET-resistant human isolates. The
tet
(O),
erm
(B), and
mreA
resistance-related genes, as well as the
bca
and
scpB
virulence-related genes, were the most frequent among the bovine isolates, while the
tet
(M),
erm
(A),
mreA
,
bca
,
lmb
, and
scpB
genes were the most prevalent among the isolates from humans. Although a few major clusters were observed, pulsed-field gel electrophoresis results revealed a variety of profiles, reflecting the substantial genetic diversity among strains of this species isolated from either humans or bovines.
Acute-Phase Concentrations of Lipopolysaccharide (LPS)-Binding Protein Inhibit Innate Immune Cell Activation by Different LPS Chemotypes via Different Mechanisms
Authors: Hamann Lutz , Alexander Christian , Stamme Cordula , Zähringer Ulrich , Schumann Ralf R.
Published: December 2004

The chain length of bacterial lipopolysaccharide (LPS) is a crucial factor for host-pathogen interaction during bacterial infection. While rough (R)-type and smooth (S)-type LPSs have been shown to differ in their ability to interact with the bactericidal/permeability-increasing protein, little is known about the differential mode of interaction with the acute-phase reactant LPS-binding protein (LBP). At lower concentrations, LBP catalyzes the binding of LPS to CD14 and enhances LPS-induced cellular activation via Toll-like receptor 4. In humans, however, concentrations of LBP in serum increase during an acute-phase response, and these LBP concentrations exhibit inhibitory effects in terms of cellular activation. The mechanisms of inhibition of LPS effects by LBP are not completely understood. Here, we report that human high-dose LBP (hd-LBP) suppresses binding of both R-type and S-type LPS to CD14 and inhibits LPS-induced nuclear translocation of NF-κB, although cellular uptake of R-type LPS was found to be increased by hd-LBP. In contrast, we found that hd-LBP enhanced the binding and uptake of S-type LPS only under serum-free conditions, whereas in the presence of serum, hd-LBP inhibited cellular binding and uptake. This inhibitory effect of serum could be mimicked by the addition of purified high-density lipoprotein (HDL) to serum-free medium, indicating an LBP-mediated transfer of preferentially S-type LPS to plasma lipoproteins such as HDL. A complete understanding of the host's mechanisms to modulate the proinflammatory effects of LPS will most likely help in the understanding of inflammation and infection and may lead to novel therapeutic intervention strategies.
Depletion of Complement Has Distinct Effects on the Primary and Secondary Antibody Responses to a Conjugate of Pneumococcal Serotype 14 Capsular Polysaccharide and a T-Cell-Dependent Protein Carrier
Authors: Test Samuel T. , Mitsuyoshi Joyce K. , Hu Yong
Published: December 2004

Complement activation plays a critical role in the immune response to T-cell-dependent and T-cell-independent antigens. However, the effect of conjugation of T-cell-dependent protein carriers to T-cell-independent type 2 antigens on the requirement for complement in the humoral immune response to such antigens remains unknown. We studied the role of complement activation on the antibody response of BALB/c mice immunized with the T-cell-independent type 2 antigen serotype 14 pneumococcal capsular polysaccharide (PPS14), either in unmodified form or conjugated to ovalbumin (OVA). In mice immunized with either PPS14 or PPS14-OVA, depletion of endogenous complement at the time of primary immunization by treatment with cobra venom factor (CVF) diminished serum anti-PPS14 concentrations after primary immunization but enhanced antibody responses after secondary immunization. The secondary immunoglobulin G (IgG) anti-PPS14 antibody response after immunization with PPS14-OVA was especially enhanced by complement depletion, was observed at doses as low as 0.2 μg of antigen, and was maximal when CVF was administered within 2 days of immunization. The avidity and opsonophagocytic functions of IgG anti-PPS14 antibodies were comparable in mice immunized with PPS14-OVA with or without complement depletion. Serum anti-PPS14 antibody concentrations were near normal, and the enhancing effects of CVF treatment on the secondary anti-PPS14 antibody response were also apparent in splenectomized mice immunized with PPS14-OVA. These results demonstrate that complement activation can have distinct effects on the primary and secondary antibody responses to a T-cell-independent type 2 antigen, either unmodified or conjugated to a T-cell-dependent protein carrier. These differences should be taken into consideration when using complement to modulate the immune response to vaccines.
Downregulation of Mitogen-Activated Protein Kinases by theBordetella bronchisepticaType III Secretion System Leads to Attenuated Nonclassical Macrophage Activation
Authors: Reissinger Annette , Skinner Jason A. , Yuk Ming H.
Published: December 2004

Bordetella bronchisepticautilizes a type III secretion system (TTSS) to establish a persistent infection of the murine respiratory tract. Previous studies have shown that theBordetellaTTSS mediated cytotoxicity in different cell types, inhibition of NF-κB in epithelial cells, and differentiation of dendritic cells into a semimature state. Here we demonstrate modulation of mitogen-activated protein kinase (MAPK) signaling pathways and altered cytokine production in macrophages and dendritic cells by theBordetellaTTSS. In macrophages, the MAPKs ERK and p38 were downregulated. This resulted in attenuated production of interleukin- (IL-)6 and IL-10. In contrast, the Th-1-polarizing cytokine IL-12 was produced at very low levels and remained unmodulated by theBordetellaTTSS. In dendritic cells, ERK was transiently activated, but this failed to alter cytokine profiles. These results suggest that theBordetellaTTSS modulates antigen-presenting cells in a cell type-specific manner and the secretion of high levels of IL-6 and IL-10 by macrophages might be important for pathogen clearance.
Dendritic Cells Activated with Products Released by Schistosome Larvae Drive Th2-Type Immune Responses, Which Can Be Inhibited by Manipulation of CD40 Costimulation
Authors: Jenkins Stephen John , Mountford Adrian Paul
Published: December 2004

The early immune events in response to infective larvae of the parasitic helminth
Schistosoma mansoni
are poorly understood, but here for the first time we report on the potential of products released by schistosome larvae (material released in the first 3 h after transformation [0-3hRP]) to stimulate the maturation of dendritic cells (DC) and alter their T-cell-polarizing function. This was performed in comparison with lipopolysaccharide (LPS) and zymosan A, which classically activate DC to prime for Th1- and Th2-type responses, respectively. In our study, immature bone marrow-derived DC stimulated in vitro with 0-3hRP exhibited up-regulated expression of major histocompatibility complex class II, CD40, and CD86 and increased production of interleukin 12p40 (IL-12p40) and IL-6, albeit at lower levels than in response to LPS or zymosan A. Using an in vitro ovalbumin peptide-restricted priming assay, DC matured with 0-3hRP exhibited a potent capacity to drive Th2 polarization of CD4
+
cells from DO11.10 transgenic mice. This was characterized by increased IL-4 production (but not gamma interferon) of a magnitude similar to that primed by DC matured with zymosan A. Inoculation of DO11.10 mice with 0-3hRP-activated DC pulsed with ovalbumin peptide also led to the development of a Th2-type polarized response in the skin-draining lymph nodes and spleen. However, ligation of CD40 on DC by anti-CD40 antibody treatment reversed the ability of 0-3hRP-activated DC to prime for Th2-type responses and instead caused the induction of a more Th1-type response.
Allele Specificity of Naturally Acquired Antibody Responses against
Plasmodium falciparum
Apical Membrane Antigen 1
Authors: Cortés Alfred , Mellombo Mata , Masciantonio Rosella , Murphy Vince J. , Reeder John C. , Anders Robin F.
Published: December 2004

Antibody responses against proteins located on the surface or in the apical organelles of merozoites are presumed to be important components of naturally acquired protective immune responses against the malaria parasite
Plasmodium falciparum
. However, many merozoite antigens are highly polymorphic, and antibodies induced against one particular allelic form might not be effective in controlling growth of parasites expressing alternative forms. The apical membrane antigen 1 (AMA1) is a polymorphic merozoite protein that is a target of naturally acquired invasion-inhibitory antibodies and is a leading asexual-stage vaccine candidate. We characterized the antibody responses against AMA1 in 262 individuals from Papua New Guinea exposed to malaria by using different allelic forms of the full AMA1 ectodomain and some individual subdomains. The majority of individuals had very high levels of antibodies against AMA1. The prevalence and titer of these antibodies increased with age. Although antibodies against conserved regions of the molecule were predominant in the majority of individuals, most plasma samples also contained antibodies directed against polymorphic regions of the antigen. In a few individuals, predominantly from younger age groups, the majority of antibodies against AMA1 were directed against polymorphic epitopes. The D10 allelic form of AMA1 apparently contains most if not all of the epitopes present in the other allelic forms tested, which might argue for its inclusion in future AMA1-based vaccines to be tested. Some important epitopes in AMA1 involved residues located in domain II or III but depended on more than one domain.
Testosterone Suppresses Protective Responses of the Liver to Blood-Stage Malaria
Authors: Krücken Jürgen , Dkhil Mohamed A. , Braun Juliane V. , Schroetel Regina M. U. , El-Khadragy Manal , Carmeliet Peter , Mossmann Horst , Wunderlich Frank
Published: December 2004

Testosterone induces a lethal outcome in otherwise self-healing blood-stage malaria caused by
Plasmodium chabaudi
. Here, we examine possible testosterone effects on the antimalaria effectors spleen and liver in female C57BL/6 mice. Self-healing malaria activates gating mechanisms in the spleen and liver that lead to a dramatic reduction in trapping activity, as measured by quantifying the uptake of 3-μm-diameter fluorescent polystyrol particles. However, testosterone delays malaria-induced closing of the liver, but not the spleen. Coincidently, testosterone causes an ∼3- to 28-fold depression of the mRNA levels of nine malaria-responsive genes, out of 299 genes tested, only in the liver and not in the spleen, as shown by cDNA arrays and Northern blotting. Among these are the genes encoding plasminogen activator inhibitor (PAI1) and hydroxysteroid sulfotransferase (STA2). STA2, which detoxifies bile acids, is suppressed 10-fold by malaria and an additional 28-fold by testosterone, suggesting a severe perturbation of bile acid metabolism. PAI1 is protective against malaria, since disruption of the PAI1 gene results in partial loss of the ability to control the course of
P. chabaudi
infections. Collectively, our data indicate that the liver rather than the spleen is a major target organ for testosterone-mediated suppression of resistance against blood-stage malaria.
CCL20/Macrophage Inflammatory Protein 3α and Tumor Necrosis Factor Alpha Production by Primary Uterine Epithelial Cells in Response to Treatment with Lipopolysaccharide or Pam3Cys
Authors: Crane-Godreau Mardi A. , Wira Charles R.
Published: December 2004

Having previously shown that CCL20/macrophage inflammatory protein 3α and tumor necrosis factor alpha (TNF-α) are released by polarized primary rat uterine epithelial cells (UEC) in response toEscherichia colibut not toLactobacillus rhamnosus, we sought to determine if epithelial cells are responsive to pathogen-associated molecular patterns (PAMP), including lipopolysaccharide (LPS), lipoteichoic acid (LTA), and Pam3Cys, a bacterial lipoprotein analog. Epithelial cells were grown to confluence on Nunc cell culture inserts prior to apical treatment with PAMPs. In response to LPS, LTA, and Pam3Cys (EMC Microcollection GmbH, Tübingen, Germany), CCL20 levels increased (4- to 10-fold) while PAMPs caused increased TNF-α (1- to 4-fold) in the medium collected after 24 h of incubation. Both apical and basolateral secretion of CCL20 and TNF-α increased in response to PAMPs, but treatments had no effect on cell viability and integrity, as measured by transepithelial resistance. Time course studies of CCL20 and TNF-α release in response to Pam3Cys and LPS indicated that CCL20 release peaked between 2 and 4 h after treatment, whereas TNF-α release was gradual over the length of the incubation. Freeze-thaw and cell lysis experiments, along with actinomycin D studies, suggested that CCL20 and TNF-α are synthesized in response to PAMP stimulation. Taken together, these studies demonstrate thatE. coliand selected PAMPs have direct effects on the production of CCL20 and TNF-α without affecting cell integrity. Since CCL20 is known to be both chemotactic and antimicrobial, the increase in apical and basolateral release by UEC in response to PAMPs suggests a new mechanism of innate immune protection in the female reproductive tract.
Differences in Patterns of Infection and Inflammation for Corticosteroid Treatment and Chemotherapy in Experimental Invasive Pulmonary Aspergillosis
Authors: Balloy Viviane , Huerre Michel , Latgé Jean-Paul , Chignard Michel
Published: December 2004

Aspergillus fumigatuscauses invasive pulmonary aspergillosis (IPA). This disease is one of the most life-threatening opportunistic infections in immunocompromised patients. The type of immunosuppressive regimen under which IPA occurs has rarely been investigated. In this study, we evaluated various parameters of the innate immune response during the progression of murine IPA induced by the intratracheal administration ofA. fumigatusconidia as a function of two immunosuppressive treatments: a corticosteroid and a chemotherapeutic agent. We compared host responses various times after infection in terms of survival, pulmonary production of pro- and anti-inflammatory cytokines, cellular trafficking in the airways, lung injury, respiratory distress, and fungal development. We found that IPA pathogenesis involved predominantly fungal development in mice treated by chemotherapy and an adverse host response in mice treated with a corticosteroid. These previously unrecognized differences should be taken into account in evaluations of the pathogenesis of IPA in animal models.
Virulent
Shigella flexneri
Causes Damage to Mitochondria and Triggers Necrosis in Infected Human Monocyte-Derived Macrophages
Authors: Koterski James F. , Nahvi Massoumeh , Venkatesan Malabi M. , Haimovich Beatrice
Published: December 2004

Shigella flexneri
is a gram-negative bacterium that causes bacillary dysentery in humans that is characterized by an acute inflammatory response of the colon. The fate of phagocytes that are infected in vitro with virulent
Shigella
has been the subject of some investigation and debate. In this study we found that virulent
Shigella
caused a rapid increase in the cell membrane permeability of infected human monocyte-derived macrophages (HMDM) but not in the cell membrane permeability of monocytes, as demonstrated by the uptake of fluorescent vital dyes. Within 2 h of infection, 59% ± 6% of the HMDM and ≤4% of the monocytes were stained with propidium iodide. Treatment of the cells with the inhibitors of caspases YVAD and zVAD, the antioxidants
N
-acetyl-
l
-cysteine and butylated hydroxyanisole, or an inhibitor of NADPH oxidase, diphenyleniodonium, did not alter the infection outcome. Importantly, we found that virulent
Shigella
caused a rapid drop in the ATP level to about 50% in infected HMDM. Furthermore, using a combination of fluorescent vital dyes and mitochondrial membrane potential-sensitive dyes, we observed that cells that exhibited a permeable cell membrane were not stained by the mitochondrion-specific dyes, indicating that the mitochondrial membrane potential was lost in these cells. We also observed infected cells that were not stained with either type of dye, indicating that the loss of the mitochondrial membrane potential preceded the increase in cell membrane permeability. Taken together, our studies showed that virulent
Shigella flexneri
targets the host cell mitochondria for destruction. This activity may account for the necrotic cell death precipitated by these pathogens.
Differential Activation of the Transcription Factor Cyclic AMP Response Element Binding Protein (CREB) in Macrophages following Infection with Pathogenic and Nonpathogenic Mycobacteria and Role for CREB in Tumor Necrosis Factor Alpha Production
Authors: Roach Shannon K. , Lee Seong-Beom , Schorey Jeffrey S.
Published: December 2004

Previous studies in our laboratory have shown a differential activation of the mitogen-activated protein kinases (MAPKs) in primary bone marrow-derived macrophages following infection with pathogenic
Mycobacterium avium
compared to the activation following infection with nonpathogenic
Mycobacterium smegmatis
. Additionally,
M. smegmatis
-infected macrophages produced significantly elevated levels of tumor necrosis factor alpha (TNF-α) compared to the levels produced by
M. avium
-infected macrophages. The TNF-α production was dependent on both p38 and extracellular signal-regulated kinase 1/2 (ERK 1/2) activation. However, the macrophage transcription factors downstream of the MAPKs, which were required for TNF-α production, remained undefined. In this study we determined that the transcription factor cyclic AMP response element binding protein (CREB) is significantly more activated in
M. smegmatis
-infected macrophages than in
M. avium
-infected macrophages. We also found that CREB activation was dependent on p38 and protein kinase A but not on ERK 1/2 or calmodulin kinase II. Moreover, mutating the cAMP-responsive element on the TNF-α promoter resulted in significantly diminished promoter activity following
M. smegmatis
infection but not
M. avium
infection. The inability of macrophages infected with
M. avium
to sustain MAPK activation and to produce high levels of TNF-α was due, in part, to an increase in serine/threonine phosphatase PP2A activity. Our studies are the first to demonstrate an important role for the transcription factor CREB in TNF-α production by mycobacterium-infected macrophages, as well as a role for
M. avium
's induction of PP2A phosphatase activity as a mechanism to limit macrophage activation.
Replication Dynamics of
Mycobacterium tuberculosis
in Chronically Infected Mice
Authors: Muñoz-Elías Ernesto J. , Timm Juliano , Botha Tania , Chan Wai-Tsing , Gomez James E. , McKinney John D.
Published: December 2004

The dynamics of host-pathogen interactions have important implications for the design of new antimicrobial agents to treat chronic infections such as tuberculosis (TB), which is notoriously refractory to conventional drug therapy. In the mouse model of TB, an acute phase of exponential bacterial growth in the lungs is followed by a chronic phase characterized by relatively stable numbers of bacteria. This equilibrium could be static, with little ongoing replication, or dynamic, with continuous bacterial multiplication balanced by bacterial killing. A static model predicts a close correspondence between “viable counts” (live bacteria) and “total counts” (live plus dead bacteria) in the lungs over time. A dynamic model predicts the divergence of total counts and viable counts over time due to the accumulation of dead bacteria. Here, viable counts are defined as bacterial CFU enumerated by plating lung homogenates; total counts are defined as bacterial chromosome equivalents (CEQ) enumerated by using quantitative real-time PCR. We show that the viable and total bacterial counts in the lungs of chronically infected mice do not diverge over time. Rapid degradation of dead bacteria is unlikely to account for the stability of bacterial CEQ numbers in the lungs over time, because treatment of mice with isoniazid for 8 weeks led to a marked reduction in the number of CFU without reducing the number of CEQ. These observations support the hypothesis that the stable number of bacterial CFU in the lungs during chronic infection represents a static equilibrium between host and pathogen.
Development of a Chinchilla Model To Allow Direct, Continuous, Biophotonic Imaging of Bioluminescent Nontypeable
Haemophilus influenzae
during Experimental Otitis Media
Authors: Novotny Laura A. , Mason Kevin M. , Bakaletz Lauren O.
Published: December 2004

We transformed a nontypeable
Haemophilus influenzae
clinical isolate with a plasmid containing the
luxCDABE
operon driven by the
H. influenzae
outer membrane protein P2 promoter. Herein, we demonstrate the ability to detect bioluminescence and to monitor infection within the nasopharynges, eustachian tubes, and middle ears of chinchillas after intranasal and transbullar challenges.
Vaccination with Purified Dr Fimbriae Reduces Mortality Associated with Chronic Urinary Tract Infection Due toEscherichia coliBearing Dr Adhesin
Authors: Goluszko Pawel , Goluszko Elzbieta , Nowicki Bogdan , Nowicki Stella , Popov Vsevolod , Wang Hui-Qun
Published: December 2004

The vaccination of C3H/HeJ mice withEscherichia coliDr fimbrial antigen reduced mortality associated with an experimental urinary tract infection due to a homologous strain bearing Dr adhesin. Immune sera with high titers of anti-Dr antibody inhibited bacterial binding to bladders and kidneys but did not affect the rate of renal colonization.
Osmolarity, a Key Environmental Signal Controlling Expression of Leptospiral Proteins LigA and LigB and the Extracellular Release of LigA
Authors: Matsunaga James , Sanchez Yolanda , Xu Xiaoyi , Haake David A.
Published: December 2004

The high-molecular-weight leptospiral immunoglobulin-like repeat (Lig) proteins are expressed only by virulent low-passage forms of pathogenic
Leptospira
species. We examined the effects of growth phase and environmental signals on the expression, surface exposure, and extracellular release of LigA and LigB. LigA was lost from stationary-phase cells, while LigB expression was maintained. The loss of cell-associated LigA correlated with selective release of a lower-molecular-weight form of LigA into the culture supernatant, while LigB and the outer membrane lipoprotein LipL41 remained associated with cells. Addition of tissue culture medium to leptospiral culture medium induced LigA and LigB expression and caused a substantial increase in released LigA. The sodium chloride component of tissue culture medium was primarily responsible for the enhanced release of LigA. Addition of sodium chloride, potassium chloride, or sodium sulfate to leptospiral medium to physiological osmolarity caused the induction of both cell-associated LigA and LigB, indicating that osmolarity regulates the expression of Lig proteins. Osmotic induction of Lig expression also resulted in enhanced release of LigA and increased surface exposure of LigB, as determined by surface immunofluorescence. Osmolarity appears to be a key environmental signal that controls the expression of LigA and LigB.
Leptin responses to short term exercise in college level male rowers
Authors: Jürimäe J , Jürimäe T
Published: December 2004

Objective:To investigate plasma leptin response to short term exercise in college level male rowers.

Methods:Thirteen rowers performed a 30 minute maximal rowing ergometer test. Venous blood samples were obtained before, immediately after, and after 30 minutes of recovery. Concentrations of leptin, insulin, growth hormone, insulin-like growth factor-I (IGF-I), and IGF binding protein-3 (IGFBP-3) were measured.

Results:Plasma leptin was significantly (p<0.05) decreased (from a mean (SD) of 2.7 (0.6) to 2.1 (0.8) ng/ml) and growth hormone significantly increased (from 0.6 (0.9) to 4.6 (5.4) μIU/l) immediately after the 30 minute maximal rowing exercise session (distance covered 7870.4 (443.3) m; blood lactate immediately after the test 14.9 (4.3) mmol/l). All other blood variables measured were not significantly changed as a result of the ergometer test. A positive relation was observed between the decreased plasma leptin concentration immediately after the test and the distance covered (R2 =  0.645; p<0.05). Changes in leptin and IGF-I concentrations immediately after the test were also related (R2 =  0.390; p<0.05). Percentage body fat explained 89.6% (p<0.05) of the variance (R2× 100) in basal leptin concentration. After normalisation for body fat, basal leptin was related (p<0.05) to basal insulin (r =  0.82) and training history (r =  −0.60).

Conclusion:Leptin is sensitive to relatively short term intense exercise when all major muscles are involved.
An analysis of the pacing strategy adopted by elite competitors in 2000 m rowing
Authors: Garland S W
Published: December 2004

Objectives:To determine the pacing strategies adopted by elite rowers in championship 2000 m races.

Methods:Split times were obtained for each boat in every heavyweight race of the Olympic Games in 2000 and World Championships in 2001 and 2002, and the top 170 competitors in the British Indoor Rowing Championships in 2001 and 2002. Data were only included in subsequent analysis if there was good evidence that the athlete or crew completed the race in the fastest possible time. The remaining data were grouped to determine if there were different strategies adopted for on-water versus ergometer trials, “winners” versus “losers”, and men versus women.

Results:Of the 1612 on-water race profiles considered, 948 fitted the inclusion criteria. There were no differences in pacing profile between winners and losers, and men and women, although on-water and ergometry trials showed a competitively meaningful significant difference over the first 500 m sector. The average profile showed that rowers performed the first 500 m of the race faster than subsequent sectors—that is, at a speed of 103.3% of the average speed for the whole race, with subsequent sectors rowed at 99.0%, 98.3%, and 99.7% of average speed for on-water rowing, and 101.5%, 99.8%, 99.0%, and 99.7% for ergometry.

Conclusions:These data indicate that all athletes or crews adopted a similar fast start strategy regardless of finishing position or sex, although the exact pace profile was dependent on rowing mode. This strategy should be considered by participants in 2000 m rowing competitions.
TOPOLOGICAL HELICITY FOR FRAMED LINKS
Authors: BOUZARTH ELIZABETH L. , RICHESON DAVID
Published: December 2004

We introduce topological helicity, an invariant for oriented framed links. Topological helicity provides an elementary means of computing helicity for a magnetic flux rope by measuring its knotting, linking, and twisting. We present an equivalence relation, reconnection-equivalence, for framed links and prove that topological helicity is a complete invariant for the resulting equivalence classes. We conclude by showing that one can use magnetic reconnection to transform one collection of linked flux ropes into another collection if and only if they have the same helicity.
Diastolic time fraction as a determinant of subendocardial perfusion
Authors: Fokkema Dirk S. , VanTeeffelen Jurgen W. G. E. , Dekker Simone , Vergroesen Isabelle , Reitsma Johannes B. , Spaan Jos A. E.
Published: December 2004

Diastolic time fraction (DTF) has been recognized as an important determinant for subendocardial perfusion, but microsphere studies in which DTF was the independent variable are practically absent. In 21 anesthetized goats, the left coronary main stem was artificially perfused at controlled pressure. DTF was varied by pacing the heart, vagus stimulation, or administration of dobutamine. Regional coronary flow was measured with fluorescent microspheres under full adenosine dilation. Perfusion pressure (Pc) was defined as mean coronary arterial pressure minus minimal left ventricular pressure. Regional flow conductances (flow/Pc) were as follows: for the subendocardium, Cendo = −0.103 + 0.197 DTF + 0.00074 Pc ( P < 0.001); for the midmyocardium, conductance = −0.048 + 0.126 DTF + 0.00049 Pc ( P < 0.001); and for the subepicardium, Cepi was not significant. Cendo-DTF relations demonstrated a finite value for DTF at which flow is zero, implying that, at physiological pressures, systolic subendocardial flow limitation extends into diastole. The DTF corresponding to an equal conductance in subendocardium and subepicardium (DTF1) was inversely related to Pc: DTF1 = 0.78 − 0.003 Pc ( P < 0.01). When heart rate and Pc were held constant and dobutamine was administered (5 goats), contractility doubled and DTF increased by 39%, resulting in an increase of Cendo of 40%. It is concluded that 1) DTF is a determinant of subendocardial perfusion, 2) systolic compression exerts a flow-limiting effect into diastole, and 3) corresponding to clinical findings on inducible ischemia we predict that, under hyperemic conditions, Cendo < Cepi if Pc is lower than ∼75% of a normal aortic pressure and heart rate >80 beats/min.
Decreased Ca2+extrusion via Na+/Ca2+exchange in epicardial left ventricular myocytes during compensated hypertrophy
Authors: Fowler Mark R. , Naz James R. , Graham Mark D. , Bru-Mercier Gilles , Harrison Simon M. , Orchard Clive H.
Published: December 2004

Hypertension-induced cardiac hypertrophy alters the amplitude and time course of the systolic Ca2+transient of subepicardial and subendocardial ventricular myocytes. The present study was designed to elucidate the mechanisms underlying these changes. Myocytes were isolated from the left ventricular subepicardium and subendocardium of 20-wk-old spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto rats (WKY; control). We monitored intracellular Ca2+using fluo 3 or fura 2; caffeine (20 mmol/l) was used to release Ca2+from the sarcoplasmic reticulum (SR), and Ni2+(10 mM) was used to inhibit Na+/Ca2+exchange (NCX) function. SHR myocytes were significantly larger than those from WKY hearts, consistent with cellular hypertrophy. Subepicardial myocytes from SHR hearts showed larger Ca2+transient amplitude and SR Ca2+content and less Ca2+extrusion via NCX compared with subepicardial WKY myocytes. These parameters did not change in subendocardial myocytes. The time course of decline of the Ca2+transient was the same in all groups of cells, but its time to peak was shorter in subepicardial cells than in subendocardial cells in WKY and SHR and was slightly prolonged in subendocardial SHR cells compared with WKY subendocardial myocytes. It is concluded that the major change in Ca2+cycling during compensated hypertrophy in SHR is a decrease in NCX activity in subepicardial cells; this increases SR Ca2+content and hence Ca2+transient amplitude, thus helping to maintain the strength of contraction in the face of an increased afterload.
Information Processing in the Mammalian Olfactory System
Authors: Lledo Pierre-Marie , Gheusi Gilles , Vincent Jean-Didier
Published: December 2004

Recently, modern neuroscience has made considerable progress in understanding how the brain perceives, discriminates, and recognizes odorant molecules. This growing knowledge took over when the sense of smell was no longer considered only as a matter for poetry or the perfume industry. Over the last decades, chemical senses captured the attention of scientists who started to investigate the different stages of olfactory pathways. Distinct fields such as genetic, biochemistry, cellular biology, neurophysiology, and behavior have contributed to provide a picture of how odor information is processed in the olfactory system as it moves from the periphery to higher areas of the brain. So far, the combination of these approaches has been most effective at the cellular level, but there are already signs, and even greater hope, that the same is gradually happening at the systems level. This review summarizes the current ideas concerning the cellular mechanisms and organizational strategies used by the olfactory system to process olfactory information. We present findings that exemplified the high degree of olfactory plasticity, with special emphasis on the first central relay of the olfactory system. Recent observations supporting the necessity of such plasticity for adult brain functions are also discussed. Due to space constraints, this review focuses mainly on the olfactory systems of vertebrates, and primarily those of mammals.
A summability factor theorem for absolute summability involving almost increasing sequences
Authors: Rhoades B. E. , Savaş Ekrem
Published: December 2004

We obtain sufficient conditions for the series ∑anλn to be absolutely summable of order k by a triangular matrix.