bluuebunny/crossref_metadata_2025_split huggingface dataset:
Raltegravir Is a Substrate for SLC22A6: a Putative Mechanism for the Interaction between Raltegravir and Tenofovir
Authors: Moss Darren M. , Kwan Wai San , Liptrott Neill J. , Smith Darren L. , Siccardi Marco , Khoo Saye H. , Back David J. , Owen Andrew 
Published: November 2010

ABSTRACT

The identification of transporters of the HIV integrase inhibitor raltegravir could be a factor in an understanding of the pharmacokinetic-pharmacodynamic relationship and reported drug interactions of raltegravir. Here we determined whether raltegravir was a substrate for ABCB1 or the influx transporters SLCO1A2, SLCO1B1, SLCO1B3, SLC22A1, SLC22A6, SLC10A1, SLC15A1, and SLC15A2. Raltegravir transport by ABCB1 was studied with CEM, CEM
VBL100
, and Caco-2 cells. Transport by uptake transporters was assessed by using a
Xenopus laevis
oocyte expression system, peripheral blood mononuclear cells, and primary renal cells. The kinetics of raltegravir transport and competition between raltegravir and tenofovir were also investigated using SLC22A6-expressing oocytes. Raltegravir was confirmed to be an ABCB1 substrate in CEM, CEM
VBL100
, and Caco-2 cells. Raltegravir was also transported by SLC22A6 and SLC15A1 in oocyte expression systems but not by other transporters studied. The

K
m

and
V
max
for SLC22A6 transport were 150 μM and 36 pmol/oocyte/h, respectively. Tenofovir and raltegravir competed for SLC22A6 transport in a concentration-dependent manner. Raltegravir inhibited 1 μM tenofovir with a 50% inhibitory concentration (IC
50
) of 14.0 μM, and tenofovir inhibited 1 μM raltegravir with an IC
50
of 27.3 μM. Raltegravir concentrations were not altered by transporter inhibitors in peripheral blood mononuclear cells or primary renal cells. Raltegravir is a substrate for SLC22A6 and SLC15A1 in the oocyte expression system. However, transport was limited compared to endogenous controls, and these transporters are unlikely to have a great impact on raltegravir pharmacokinetics.
Molecular Assessment of
Plasmodium falciparum
Resistance to Antimalarial Drugs in Papua New Guinea Using an Extended Ligase Detection Reaction Fluorescent Microsphere Assay
Authors: Wong Rina P. M. , Karunajeewa Harin , Mueller Ivo , Siba Peter , Zimmerman Peter A. , Davis Timothy M. E. 
Published: November 2010

ABSTRACT

Surveillance for
Plasmodium falciparum
drug resistance mutations is becoming an established tool for assessing antimalarial treatment effectiveness. We used an extended version of a high-throughput post-PCR multiplexed ligase detection reaction fluorescent microsphere assay (LDR-FMA) to detect single-nucleotide
P. falciparum
drug resistance polymorphisms in 402 isolates from children in Papua New Guinea (PNG) participating in an antimalarial treatment trial. There was a fixation of
P. falciparum crt
(
pfcrt
) K76T,
pfdhfr
C59R and S108N, and
pfmdr1
mutations (92%, 93%, 95%, and 91%, respectively). Multiple mutations were frequent. Eighty-eight percent of isolates possessed a quintuple mutation (underlined),
S
VMN
T
, N
RN
I, KAA, and
Y
YSND, in codons 72 to 76 for
pfcrt
; 51, 59, 108, and 164 for
pfdhfr
; 540, 581, and 613 for
pfdhps
; and 86, 184, 1034, 1042, and 1246 for
pfmdr1
, and four of these carried the K540E
pfdhps
allele. The
pfmdr1
D1246Y mutation was associated with PCR-corrected day 42
in vivo
treatment failure in children allocated piperaquine-dihydroartemisinin (
P
= 0.004). Although the
pfmdr1
NFSDD haplotype was found in only four isolates, it has been associated with artemether-lumefantrine treatment failure in Africa. LDR-FMA allows the large-scale assessment of resistance-associated single-nucleotide polymorphisms (SNPs). Our findings reflect previous heavy 4-aminoquinoline/sulfadoxine-pyrimethamine use in PNG. Since artemether-lumefantrine and piperaquine-dihydroartemisinin will become first- and second-line treatments, respectively, the monitoring of
pfmdr1
SNPs appears to be a high priority.
Human Tissue Distribution of Voriconazole
Authors: Weiler Stefan , Fiegl David , MacFarland Róisín , Stienecke Eva , Bellmann-Weiler Rosa , Dunzendorfer Stefan , Joannidis Michael , Bellmann Romuald 
Published: November 2010

ABSTRACT
Voriconazole concentrations were determined in autopsy samples of eight patients who had been treated for a median of 7 days (interquartile range [IQR], 5 days). Voriconazole penetrates well into various tissues, with median levels of 6.26 μg/g ((interquartile range [IQR], 7.87 μg/g) in the lung, 3.41 μg/g (IQR, 16.72 μg/g) in the brain, 6.89 μg/g (IQR, 24.16 μg/g) in the liver, 6.47 μg/g (IQR, 6.19 μg/g) in the kidneys, 5.60 μg/g (IQR, 11.49 μg/g) in the spleen, and 7.55 μg/g (IQR, 16.91 μg/g) in the myocardium.
rmtD2
, a New Allele of a 16S rRNA Methylase Gene, Has Been Present in
Enterobacteriaceae
Isolates from Argentina for More than a Decade
Authors: Tijet Nathalie , Andres Patricia , Chung Catherine , Lucero Celeste , Low Donald E. , Galas Marcelo , Corso Alejandra , Petroni Alejandro , Melano Roberto G. 
Published: November 2010

ABSTRACT

The first allele of a 16S rRNA methyltransferase gene,
rmtD2
, conferring very high resistance to all clinically available aminoglycosides, was detected in 7/1,064 enterobacteria collected in 2007.
rmtD2
was located on a conjugative plasmid in a Tn
2670
-like element inside a structure similar to that of
rmtD1
but probably having an independent assembly.
rmtD2
has been found since 1996 to 1998 mainly in
Enterobacter
and
Citrobacter
isolates, suggesting a possible reservoir in these genera. This presumption deserves monitoring by continuous surveillance.
An A643V Amino Acid Substitution in Upc2p Contributes to Azole Resistance in Well-Characterized Clinical Isolates of
Candida albicans
Authors: Hoot Samantha J. , Smith Adam R. , Brown Ryan P. , White Theodore C. 
Published: November 2010

ABSTRACT

The
Candida albicans
Upc2p transcription factor regulates
ERG11
, encoding the target of azole drugs. Gain-of-function mutations that contribute to resistance were recently identified in a series of sequential clinical isolates (N. Dunkel, T. T. Liu, K. S. Barker, R. Homayouni, J. Morschhauser, and P. D. Rogers, Eukaryot. Cell 7:1180-1190, 2008). In the present study,
UPC2
was sequenced from a matched set of 17 isolates. An A643V substitution was present in all of the isolates in the series that overexpressed
ERG11
. Azole susceptibility, ergosterol levels, and expression of
ERG
genes were elevated in the A643V clinical isolates and in reconstructed strains.
Herb-Drug Interaction betweenEchinacea purpureaand Darunavir-Ritonavir in HIV-Infected Patients
Authors: Moltó José , Valle Marta , Miranda Cristina , Cedeño Samandhy , Negredo Eugenia , Barbanoj Manuel José , Clotet Bonaventura 
Published: November 2010

ABSTRACTThe aim of this open-label, fixed-sequence study was to investigate the potential ofEchinacea purpurea, a commonly used botanical supplement, to interact with the boosted protease inhibitor darunavir-ritonavir. Fifteen HIV-infected patients receiving antiretroviral therapy including darunavir-ritonavir (600/100 mg twice daily) for at least 4 weeks were included.E. purpurearoot extract capsules were added to the antiretroviral treatment (500 mg every 6 h) from days 1 to 14. Darunavir concentrations in plasma were determined by high-performance liquid chromatography immediately before and 1, 2, 4, 6, 8, 10, and 12 h after a morning dose of darunavir-ritonavir on days 0 (darunavir-ritonavir) and 14 (darunavir-ritonavir plus echinacea). Individual darunavir pharmacokinetic parameters were calculated by noncompartmental analysis and compared between days 0 and 14 with the geometric mean ratio (GMR) and its 90% confidence interval (CI). The median age was 49 (range, 43 to 67) years, and the body mass index was 24.2 (range, 18.7 to 27.5) kg/m2. Echinacea was well tolerated, and all participants completed the study. The GMR for darunavir coadministered with echinacea relative to that for darunavir alone was 0.84 (90% CI, 0.63-1.12) for the concentration at the end of the dosing interval, 0.90 (90% CI, 0.74-1.10) for the area under the concentration-time curve from 0 to 12 h, and 0.98 (90% CI, 0.82-1.16) for the maximum concentration. In summary, coadministration ofE. purpureawith darunavir-ritonavir was safe and well tolerated. Individual patients did show a decrease in darunavir concentrations, although this did not affect the overall darunavir or ritonavir pharmacokinetics. Although no dose adjustment is required, monitoring darunavir concentrations on an individual basis may give reassurance in this setting.
Recent Exposure to Caspofungin or Fluconazole Influences the Epidemiology of Candidemia: a Prospective Multicenter Study Involving 2,441 Patients
Authors: Lortholary Olivier , Desnos-Ollivier Marie , Sitbon Karine , Fontanet Arnaud , Bretagne Stéphane , Dromer Françoise 
Published: November 2010

ABSTRACT

A prospective multicenter surveillance program on yeast bloodstream infections was implemented in the Paris, France, area without restrictions on ward of hospitalization (intensive care unit, hematology, and surgery) or age (adults and children). The present analysis concerns 2,618 isolates collected over 7 years from 2,441 patients. Centralized species identification and antifungal susceptibility testing using the EUCAST methodology were performed. Almost 10% (232/2,441) of the patients had recently (≤30 days) been treated with antifungal drugs. We analyzed the effect of recent exposure to fluconazole (
n
= 159) or caspofungin (
n
= 61) on the proportions of the five major
Candida
species. For both drugs, preexposure was associated with a decreased prevalence of
Candida albicans
in favor of less drug-susceptible species (
C. glabrata
and
C. krusei
for the former and
C. parapsilosis
and, to a lesser extent,
C. glabrata
and
C. krusei
for the latter;
P
= 0.001). In the multivariate analysis, the risk of being infected with an isolate with decreased susceptibility to fluconazole was independently associated with an age of ≥15 years (odds ratio [OR] = 2.45; 95% confidence interval [CI] = 1.39 to 4.31;
P
= 0.002) and with recent exposure to fluconazole (OR = 2.17; 95% CI = 1.51 to 3.13;
P
< 0.001), while the risk of being infected with an isolate with decreased susceptibility to caspofungin was independently associated with an age <15 years (OR = 2.53; 95% CI = 1.43 to 4.48;
P
= 0.001) and with recent exposure to caspofungin (OR = 4.79; 95% CI = 2.47 to 9.28;
P
< 0.001). These findings could influence future recommendations for the management of candidemia.
Amiodarone Inhibits
Trypanosoma cruzi
Infection and Promotes Cardiac Cell Recovery with Gap Junction and Cytoskeleton Reassembly
In Vitro
Authors: Adesse Daniel , Meirelles Azzam Eduardo , de Nazareth L. Meirelles Maria , Urbina Julio A. , Garzoni Luciana R. 
Published: November 2010

ABSTRACT

We present the results of the first detailed study of the antiproliferative and ultrastructural effects of amiodarone on
Trypanosoma cruzi
, the causative agent of Chagas' disease. Moreover, we report the effects of this compound on the recovery of F-actin fibrils, connexin43, and contractility in
T. cruzi
-infected cardiac myocytes. Amiodarone is the most prescribed class III antiarrhythmic agent and is frequently used for the symptomatic treatment of Chagas' disease patients with cardiac compromise. In addition, recent studies identified its antifungal and antiprotozoal activities, which take place through Ca
2+
homeostasis disruption and ergosterol biosynthesis blockade. We tested different concentrations of amiodarone (2.5 to 10 μM) on infected primary cultures of heart muscle cells and observed a dose- and time-dependent effect on growth of the clinically relevant intracellular amastigote form of
T. cruzi
. Ultrastructural analyses revealed that amiodarone had a profound effect on intracellular amastigotes, including mitochondrial swelling and disorganization of reservosomes and the kinetoplast and a blockade of amastigote-trypomastigote differentiation. Amiodarone showed no toxic effects on host cells, which recovered their F-actin fibrillar organization, connexin43 distribution, and spontaneous contractility concomitant with the drug-induced eradication of the intracellular parasites. Amiodarone is, therefore, a promising compound for the development of new drugs against
T. cruzi
.
Pre-Steady-State Kinetic Analysis of the Incorporation of Anti-HIV Nucleotide Analogs Catalyzed by Human X- and Y-Family DNA Polymerases
Authors: Brown Jessica A. , Pack Lindsey R. , Fowler Jason D. , Suo Zucai 
Published: November 2010

ABSTRACTNucleoside reverse transcriptase inhibitors (NRTIs) are an important class of antiviral drugs used to manage infections by human immunodeficiency virus, which causes AIDS. Unfortunately, these drugs cause unwanted side effects, and the molecular basis of NRTI toxicity is not fully understood. Putative routes of NRTI toxicity include the inhibition of human nuclear and mitochondrial DNA polymerases. A strong correlation between mitochondrial toxicity and NRTI incorporation catalyzed by human mitochondrial DNA polymerase has been established bothin vitroandin vivo. However, it remains to be determined whether NRTIs are substrates for the recently discovered human X- and Y-family DNA polymerases, which participate in DNA repair and DNA lesion bypassin vivo. Using pre-steady-state kinetic techniques, we measured the substrate specificity constants for human DNA polymerases β, λ, η, ι, κ, and Rev1 incorporating the active, 5′-phosphorylated forms of tenofovir, lamivudine, emtricitabine, and zidovudine. For the six enzymes, all of the drug analogs were incorporated less efficiently (40- to >110,000-fold) than the corresponding natural nucleotides, usually due to a weaker binding affinity and a slower rate of incorporation for the incoming nucleotide analog. In general, the 5′-triphosphate forms of lamivudine and zidovudine were better substrates than emtricitabine and tenofovir for the six human enzymes, although the substrate specificity profile depended on the DNA polymerase. Our kinetic results suggest NRTI insertion catalyzed by human X- and Y-family DNA polymerases is a potential mechanism of NRTI drug toxicity, and we have established a structure-function relationship for designing improved NRTIs.
Using Bioluminescence To Monitor Treatment Response in Real Time in Mice with
Mycobacterium ulcerans
Infection
Authors: Zhang Tianyu , Li Si-Yang , Converse Paul J. , Almeida Deepak V. , Grosset Jacques H. , Nuermberger Eric L. 
Published: November 2010

ABSTRACT

Mycobacterium ulcerans
causes Buruli ulcer, a potentially disabling ulcerative skin disease. Only recently was antimicrobial therapy proven effective. Treatment for 2 months with rifampin plus streptomycin was first proposed after experiments in the mouse footpad model demonstrated bactericidal activity. This treatment is now considered the treatment of choice, although larger ulcers may require adjunctive surgery. Shorter, oral regimens are desired, but evaluating drug activity in mice is hampered by the very slow growth of
M. ulcerans
, which takes 3 months to produce countable colonies. We created a recombinant bioluminescent
M. ulcerans
strain expressing
luxAB
from
Vibrio harveyi
for real-time evaluation of antimicrobial effects
in vivo
. Mouse footpads were injected with wild-type
M. ulcerans
1059 (WtMu) or the recombinant bioluminescent strain (rMu). Two weeks later, mice received rifampin plus streptomycin, kanamycin alone (to which rMu is resistant), or streptomycin alone for 4 weeks and were observed for footpad swelling (preventive model). Untreated controls and kanamycin-treated rMu-infected mice received rifampin plus streptomycin for 4 weeks after developing footpad swelling (curative model). Compared to WtMu, rMu exhibited similar growth and virulence
in vivo
and similar drug susceptibility. A good correlation was observed between luminescence (measured as relative light units) and number of viable bacteria (measured by CFU) in footpad homogenates. Proof of concept was also shown for serial real-time evaluation of drug activity in live mice. These results indicate the potential of bioluminescence as a real-time surrogate marker for viable bacteria in mouse footpads to accelerate the identification of new treatments for Buruli ulcer.
Role of
Tannerella forsythia
NanH Sialidase in Epithelial Cell Attachment
Authors: Honma Kiyonobu , Mishima Elina , Sharma Ashu 
Published: November 2010

ABSTRACT

Tannerella forsythia
is a Gram-negative oral anaerobe which contributes to the development of periodontitis, an inflammatory disease of the tooth-supporting tissues leading to tooth loss. The mechanisms by which this bacterium colonizes the oral cavity are poorly understood. The bacterium has been shown to express two distinct sialidases, namely, SiaHI and NanH, with the latter being the major sialidase. Bacterial sialidases can play roles in pathogenesis by cleaving sialic acids on host glycoproteins, destroying their integrity, and/or unmasking hidden epitopes on host surfaces for colonization. In the present study, we investigated the roles of the SiaHI and NanH sialidases by generating and characterizing specific deletion mutants. Our results showed that the NanH deficiency resulted in a total loss of sialidase activity associated with the outer-membrane and secreted fractions. On the other hand, the SiaHI deficiency resulted in only a slight reduction in the total sialidase activity, with no significant differences in the levels of sialidase activity in the outer membrane or secreted fractions compared to that in the wild-type strain. The results demonstrated that NanH is both surface localized and secreted. The NanH-deficient mutant but not the SiaHI-deficient mutant was significantly attenuated in epithelial cell binding and invasion abilities compared to the wild-type strain. Moreover, the NanH-deficient mutant alone was impaired in cleaving surface sialic acids on epithelial cells. Thus, our study suggests that NanH sialidase might play roles in bacterial colonization by exposing sialic acid-hidden epitopes on epithelial cells.
Proinflammatory Cytokine Gene Expression in the Stomach Correlates with Vaccine-Induced Protection against
Helicobacter pylori
Infection in Mice: an Important Role for Interleukin-17 during the Effector Phase
Authors: Flach Carl-Fredrik , Östberg Anna Karin , Nilsson Anne-Therese , Malefyt Rene De Waal , Raghavan Sukanya 
Published: November 2010

ABSTRACT

CD4
+
T cells have been shown to be essential for vaccine-induced protection against
Helicobacter pylori
infection in mice. Less is known about the relative contributions of individual cell subpopulations, such as T
h
1 and T
h
17 cells, and their associated cytokines. The aim of the present study was to find immune correlates to vaccine-induced protection and further study their role in protection against
H. pylori
infection. Immunized and unimmunized mice were challenged with
H. pylori
, and immune responses were compared. Vaccine-induced protection was assessed by measuring
H. pylori
colonization in the stomach. Gastric gene expression of T
h
1- and/or T
h
17-associated cytokines was analyzed by quantitative PCR, and contributions of individual cytokines to protection were evaluated by antibody-mediated
in vivo
neutralization. By analyzing immunized and unimmunized mice, a significant inverse correlation between the levels of interleukin-12p40 (IL-12p40), tumor necrosis factor alpha (TNF), gamma interferon (IFN-γ), and IL-17 gene expression and the number of
H. pylori
bacteria in the stomachs of individual animals after challenge could be demonstrated. In a kinetic study, upregulation of TNF, IFN-γ, and IL-17 coincided with vaccine-induced protection at 7 days after
H. pylori
challenge and was sustained for at least 21 days.
In vivo
neutralization of these cytokines during the effector phase of the immune response revealed a significant role for IL-17, but not for IFN-γ or TNF, in vaccine-induced protection. In conclusion, although both T
h
1- and T
h
17-associated gene expression in the stomach correlate with vaccine-induced protection against
H. pylori
infection, our study indicates that mainly T
h
17 effector mechanisms are of critical importance to protection.
Characterization of Avian γδ T-Cell Subsets afterSalmonella entericaSerovar Typhimurium Infection of Chicks
Authors: Pieper Jana , Methner Ulrich , Berndt Angela 
Published: November 2010

ABSTRACTAvian γδ T lymphocytes are frequently found in blood and organs and are assumed to be crucial to the immune defense againstSalmonellainfections of chicks. To elucidate the so-far-unknown immunological features of subpopulations of avian γδ T cells in the course of infection, day-old chicks were infected orally withSalmonella entericaserovar Typhimurium. Until 11 days after infection, the occurrence as well as transcription of the CD8 antigen and immunologically relevant protein genes of CD8α−and CD8α+high(CD8αα+CD8αβ+) γδ cells were analyzed using flow cytometry and quantitative real-time reverse transcription-PCR (RT-PCR) with blood, spleen, thymus, and cecum samples. After infection, an increased percentage of CD8α+highγδ T lymphocytes was found in blood, in spleen, and, with the highest values and most rapidly, in cecum. Within the CD8α+highsubset, a significant rise in the number of CD8αα+cells was accompanied by enhanced CD8α antigen expression and reduced gene transcription of the CD8β chain. CD8αα+and CD8αβ+cells showed elevated transcription for Fas, Fas ligand (FasL), interleukin-2 receptor α (IL-2Rα), and gamma interferon (IFN-γ). While the highest fold changes in mRNA levels were observed in CD8αβ+cells, the mRNA expression rates of CD8αβ+cells never significantly exceeded those of the CD8αα+cells. In conclusion, both CD8α+highγδ T-cell subpopulations (CD8αα+and CD8αβ+) might be a potential source of IFN-γ inSalmonella-infected chicks. However, due to their prominent frequency in blood and organs after infection, the avian CD8αα+γδ T-cell subset seems to be unique and of importance in the course ofSalmonellaTyphimurium infection of very young chicks.
Identification of a Family of Effectors Secreted by the Type III Secretion System That Are Conserved in Pathogenic Chlamydiae
Authors: Muschiol Sandra , Boncompain Gaelle , Vromman François , Dehoux Pierre , Normark Staffan , Henriques-Normark Birgitta , Subtil Agathe 
Published: November 2010

ABSTRACT

Chlamydiae are Gram-negative, obligate intracellular pathogens that replicate within a membrane-bounded compartment termed an inclusion. Throughout their development, they actively modify the eukaryotic environment. The type III secretion (TTS) system is the main process by which the bacteria translocate effector proteins into the inclusion membrane and the host cell cytoplasm. Here we describe a family of type III secreted effectors that are present in all pathogenic chlamydiae and absent in the environment-related species. It is defined by a common domain of unknown function, DUF582, that is present in four or five proteins in each
Chlamydiaceae
species. We show that the amino-terminal extremity of DUF582 proteins functions as a TTS signal. DUF582 proteins from
C. trachomatis
CT620, CT621, and CT711 are expressed at the middle and late phases of the infectious cycle. Immunolocalization further revealed that CT620 and CT621 are secreted into the host cell cytoplasm, as well as within the lumen of the inclusion, where they do not associate with bacterial markers. Finally, we show that DUF582 proteins are present in nuclei of infected cells, suggesting that members of the DUF582 family of effector proteins may target nuclear cell functions. The expansion of this family of proteins in pathogenic chlamydiae and their conservation among the different species suggest that they play important roles in the infectious cycle.